Class 6

MP Board Class 6th Science Solutions Chapter 8 Body Movement

Body Movement Textbook Exercises

Question 1.
Fill in the blanks:

1. Joints of the bones help in the ……………………… of the body.
2. A combination of bones and cartilages forms the …………………… of the body.
3. The bones at the elbow are joined by a …………………….. joint.
4. The contraction of the …………………….. pulls the bones during movement.

Answer:

1. Movement
2. Skeleton
3. Balls socket
4. Muscles.

Question 2.
Indicate true (T) and false (F) among the following sentences.

1. The movement and locomotion of all animals is exactly the same.
2. The cartilages are harder than bones.
3. The finger bones do not have joints.
4. The fore arm has two bones.
5. Cockroaches have an outer skeleton.

Answer:

1. False
2. False
3. False
4. True
5. True.

Question 3.
Match the items in Column I with one or more items of Column II.

Answer:

(i) – (d)
(ii) – (a) and (g)
(iii) – (e)
(iv) – (f)
(v) – (b) and (c).

Question 4.
Answer the following:

Question (a)
What is a ball and socket joint?
Answer:
The round end of one bone fits into the hollow space of the other bone. Such a kind of joint allows movements in all directions. Such joints are called ball and socket joints.

Question (b)
Which of the skull bones are movable?
Answer:
The facial bones of our skull comprises upper and lower jaw, in which lower jaws is movable.

Question (c)
Why can our elbow not move backwards?
Answer:
Elbow cannot move backwards because it has hinge joint which allows only back and forth movements.

Projects And Activities

Activity 1.
Make a table to show how do animals move from place to place?
Answer:
Movement of Animals

Activity 2.
Make a table to show the movements of different parts in our body?
Answer:
Movement of different parts in our body:

Activity 3.
Observe a cockroach and explain how is it move?
Answer:
Cockroaches walk and climb as well as fly in the air. They have three pairs of legs. These help in walking. The body is covered with a hard outer skeleton. This outer skeleton is made of different units joined together and that permits movement.

There are two pairs of wings attached to the breast. The cockroaches have distinct muscles those near the legs move the legs for walking. The breast muscles move the wings when the cockroach flies.

Body Movement Intex Questions

Question 1.
Boojho wonders about movements in plants. He knows they do not move from place to place, but, do they show any other kind of movement?
Answer:
Yes

Body Movement Additional Important Questions

Body Movement Objective Type Questions

Choose the correct answer:

Question (a)
Our finger has ……………………… bones?
(a) 2
(b) 3
(c) 4
(d) 5
Answer:
(b) 3

Question (b)
Cockroach has …………………….. pairs of joint legs?
(a) 2
(b) 3
(c) 4
(d) 5
Answer:
(b) 3

Question (c)
Our skeleton has bones?
(a) 206
(b) 306
(c) 406
(d) None of these
Answer:
(a) 206

Question 2.
Fill in the blanks:

1. The animals which has back bone are called …………………………..
2. The back bone has ………………………… regions.
3. Our foot has ………………………… longer bones.
4. In the fore – arm, there are ………………………. bones.
5. Fishes move in water with the help of ………………………….
6. The ancient Greek philosopher …………………………… write the book on “Gait of Animals”.
7. Snails move with the help of a ……………………………… foot.

Answer:

1. Vertebrate
2. Five
3. Five
4. Two long
5. Fins
6. Aristotle
7. Muscular.

Question 3.
Which of the following statements are true (T) or false (F):

1. We have ten organ systems.
2. Cartilage is hard and bones are soft.
3. The place where two or more bones meet together is called a joint.
4. The hard covers of crabs and insects are called exoskeleton.
5. Strong muscles and light bones work together to help the birds fly.
6. We can bend or. move our body only at those points where bones meet.

Answer:

1. True
2. False
3. True
4. True
5. True
6. True.

Question 4.
Match the items in Column A with the Column B:

Answer:

(i) – (d)
(ii) – (e)
(iii) – (a)
(iv) – (c)
(v) – (b)

Body Movement Very Short Answer Type Questions

Question 1.
How are animals move from are place to another?
Answer:
The animals move from one place to another by one of the following ways: Walk, run, jump, creep, fly, slither, swim and crawl.

Question 2.
Do you get a feel of something hard pressing against your fingers?
Answer:
Yes, the hard structures are the bones.

Question 3.
What are joints?
Answer:
The places (points) where we are able to bend or rotate our body.

Question 4.
How are bones joined together?
Answer:
Bones are held together at joints by strong cords called ligaments.

Question 5.
What are hinge joints?
Answer:
These joints allow movement only in one plane not more than 180 degrees.

Question 6.
Name any two parts of your body which you are able to (i) bend (ii) rotate?
Answer:

1. Elbow
2. Arms.

Question 7.
Where do you find hinge joints?
Answer:
Knee and Elbow.

Question 8.
How do muscles move the bones?
Answer:
The muscles move the bones by contraction.

Question 9.
What is ball and socket joint?
Answer:
The rounded end of one bone fits into the cavity of the other bone is called as ball and socket joint.

Question 10.
Where do you find pivotal joint?
Answer:
The joint where our neck joints the head is a pivotal joint.

Question 11.
Define movement?
Answer:
When organisms move their body parts without changing their position.

Question 12.
Define fixed joints?
Answer:
The joint where movement of bone is not allowed is called fixed joint.

Question 13.
What is skeleton?
Answer:
All the bones in our body form a framework to give a shape to our body. This framework is called the skeleton.

Question 14.
What is locomotion?
Answer:
When animals move from one place to another place. This kind of movement is called locomotion.

Question 15.
Define cartilage?
Answer:
The cartilage is additional part of skeleton, not as hard as the bone and can be bent.

Question 16.
Is cartilage also found in the joints of the body?
Answer:
Yes.

Question 17.
How may bones are there in human skeleton?
Answer:
There are 206 bones in human skeleton.

Question 18.
What is X – rays?
Answer:
The X – rays show the shapes of the bones in our bodies.

Question 19.
Define skull?
Answer:
The skull is made of many bones joined together. It encloses and protects a very important part of the body, the brain.

Question 20.
How do fishes move?
Answer:
They move with the help of tail fins and anal fines.

Question 21.
Does the earthworm have bones?
Answer:
No.

Question 22.
How does a cockroach move?
Answer:
Cockroach has distinct muscles attached with skeleton process. These muscles move the body.

Question 23.
What is streamlined?
Answer:
The lead and tail of the fish are smaller than the middle portion, of the body. The body’tapers at both ends. This body shape is called streamlined.

Question 24.
How does snails move?
Answer:
The snails move with the help of a muscular food.

Body Movement Short Answer Type Questions

Question 1.
What are bone joints and from what are they joint?
Answer:
The place where two bones or more than two bones meet together is called a joint. There are various kinds of joints. They are held together at joints by strong cords called ligaments.

Question 2.
Define pivotal joint?
Answer:
The joint where our neck joins the head is called pivotal joint. It allows us to bend our head forward and backward and turn the head to our left or right. In a pivotal joint a cylindrical bone rotates in a ring. Thus, we can say that pivotal joint is a very important joint for our body.

Question 3.
Draw a diagram of hinge joints?
Answer:
The hinge joint allows a back and forth movement. For example, the elbow has a hinge joint that allows only a back and forth movement.

Question 4.
Describe rib cage with the help of a diagram?
Answer:
Just feel your chest bones and the back bone by gently pressing the middle of the chest and back at the same time. From the figure also, we see that the ribs are curiously bent. They join the chest bone and the backbone together to form a box. This is called the rib cage. Some important internal parts of our body lie protected inside this cage.

Question 5.
How many regions are there is our backbone? Draw the diagram of backbone also?
Answer:
The backbone has five regions. From the top they are the neck, chest, hip, tail and belly regions. The five vertebrae of the hip are inseparable. They are fused together. The four vertebrae of the tail are also fuse.

Body Movement Long Answer Type Questions

Question 1.
Define with diagram the bones present in our hand?
Answer:
The hand comprises the upper arm, fore – arm, wrist, palm and fingers. The upper arm has one long bone, and forearm has two long bones. Wrist is made up of several small bones. The palm is composed of fine slightly longer bones. There are three small bones in each finger.

Question 2.
Define shoulder bones and pelvic bones with neat diagrams?
Answer:
If some one stands pressing against a wall, two bones becomes visible at the shoulder. These are called shoulder bones. While as shown in Fig. (b), this Fig. Bones of the hand. structure is made of pelvic bones. They enclose the portion of your body below the stomach. This is the part you sit on.

Question 3.
How many parts does our skull have? Draw its diagram also?
Answer:
Our skull has two main parts i.e., cranium or the brain case and the facial bone. The bones of cranium are flat and held firmly. It protects brain, the facial bones comprise upper and lower jaw. Lower jaw is movable. The’ skull has a pair of eye sockets. Fig. The skull.

Question 4.
Draw the diagram of the human skeleton?
Answer:

Question 5.
Draw the diagram of skeleton of a bird?
Answer:

Question 6.
Define the movement of snake?
Answer:
Snakes have a long backbone. They have many thin muscles. They are connected to each other even though they are far from one another. They also interconnect the backbone, ribs and skin. The snake’s body curves into many loops.

Each loop of the snake gives it a forward push by pressing against the ground. Since its long body makes many loops and each loop gives it this push, the snake moves forward very fast and not in a straightline.

MP Board Class 6th Science Solutions

MP Board Class 6th Science Solutions Chapter 16 Garbage In, Garbage Out

Garbage In, Garbage Out Textbook Exercises

Question 1.

1. Which kind of garbage is not converted into compost by the redworms?
2. Have you seen any other organism beside redworms, in your pit? If yes, try to find out their names. Draw pictures of these?

Answer:
1. Garbage such as pieces of polythene bags, cloth, nails, old shoes, broken glass, broken toys and aluminimum wrappers etc. are not into compost by the red worms.

2. Yes, there are some other organisms in a pit of composting such as fungi and bacteria which decompose the biodegradable wastes.

Question 2.
Discuss:

1. Is garbage disposal the responsibility only of the government?
2. Is it possible to reduce the problems relating to disposal of garbage?

Answer:
1. No, it is also our responsibility. Because fresh air, water and locality helps us to make healthy. So, every citizen should care for waste disposal. We should not throw the wastes carelessly. We collect all the garbage carefully in dustbins and should save environment to pollute.

2. Yes, it is possible to reduce the problems relating to disposal of garbage by using re – cycleable materials.

Question 3.

1. What do you do with the left over food at home?
2. If you and your friends are given the choice of eating in a plastic plate or a banana leaf platter at a party, which one would you prefer and why?

Answer:

1. Preserve properly the left over food and reuse. Convert it to some other food preparation and consume.
2. In a party I and my friends choose to eat in a banana leaf platter, due to the following reasions.
   • It is easy disposal,
   • It can be recycled,
   • It is more environment friendly.

Question 4.

1. Collect pieces of different kinds of paper. Find out which of these can be recycled?
2. With the help of a lens look at the pieces of paper you collected for the above question. Do you see any difference in the material of recycled paper and a new sheet of paper?

Answer:
1. We collected the pieces of old newspapers, used envelopes, notebooks, magazines, any other paper like shiny, plastic coated paper. Except plastic coated and shiny papers, all other papers can be recycled.

2. When we see the recycled paper with the help of lense, we find that there is a difference in quality of paper. The recycled paper is more thick and more rough as compared to new sheet of paper.

Question 5.

1. Collect different kinds of packaging material What was the purpose for which each one was used? Discuss in groups.
2. Give an example in which packaging could have been reduced?
3. Write a story on how packaging increases the amount of garbage.

Answer:
(a)

• Paper pakcet : Light food items
• Wooden boxes : Delicate items
• Card board : Crockery
• Glass covers : Show pieces
• Plastic covers : Dresses and clothes.

(b) The shopkeepers should buy large amount of goods like sugar, dal, nuts, etc. By doing so they reduce the waste and packaging materials. They should buy goods in bulk and bigger quantities in a single package. This type of shopping will reduce the wastages.

(c) Packing increases the amount of garbages. Every good or things are sold in small packets of plastic materials which are thrown out after use. This increases the garbage. Cans, small aluminium foils, plastic bags and many other packaging materials are used and thrown out after use. These packaging materials also increase garbage.

Now – a – days every goods and things such as soaps, detergents, ghee, refined oil and many more eatable goods are generally sold in small pockets. This also increase the garbage upto a large extent. In this way we can say that packaging materials increases the amount of garbage.

Question 6.
Do you think it is better to use compost instead of chemical fertilizers? Why?
Answer:
We think that compost is better to use instead of chemical fertilizers. Compost fertilizers are those in which plants and animal extracts etc. are used. These fertilizers usually contain all nutrients in varying proportions. These fertilizers are not made in factories. They are prepared by the farmers themselves using indigenous methods.

They contain a large measure of organic matter. No special precautions are required while using them. In this category includes gobar khad, compost or the mixture made out of organic waste and human excreta, green manure and oil cakes etc.

Chemical fertilizer are manufactured artificially in factories with the use of chemicals. These contain large amounts of plant nutrients. These contain only one and two or three nutritional elements. For examples, Urea, Ammonium Sulphate, Super Phosphate, Potassium Sulphate, Sodium Nitrate, Calcium Sulphate etc.

Projects and Activity

Activity 1.
Make a comfortable home for our redworms in the pit or the box.
Answer:
Let us dig a pit about 30 cm deep or keep a wooden box at a place, which is neither two hot nor too cold. Spread a net or chicken mesh at the bottom of the pit or the box. You can also spread 1 or 2 cm thick layer of sand as an alternative. Now, spread some vegetable wastes including peels of fruits over this layer of sand.

One can also use green leaves, pieces of dried stalks of plants, husk or pieces of newspaper or carboard to spread over the layer of sand. However, shiny or plastic coated paper should not be used for this purpose. Dried animal dung could also be used as a spread over sand or wire mesh. Sprinkle some water to make this layer wet.

Take care not to use excess of water. Do not press the layer of waste. Keep this layer loose so that it has sufficient air and moisture. Now, your pit is ready to welcome the redworms. Buy some redworms and put them in your pit [Fig.]. Cover them loosely with a gunny bag or an old sheet of cloth or a layer of grass.

Garbage In, Garbage Out Text Book Questions

Question 1.
Paheli did wonder as to what could be useful garbage? Why was it thrown away in the first place? Is there some garbage that is not actually garbage?
Answer:
The useful garbage are ped of vegetables and fruits, egg shell, tea leaves, paper bags, pieces of paper, etc. Any garbage that can be recycled is not actually a garbage.

Question 2.
Paheli would like to suggest that containers used for storing poisonous substances should be recycled separately and that such recycled plastics are not used to make plastic bags.
Answer:
It is absolutly correct.

Garbage In, Garbage Out Additional Important Questions

Garbage In, Garbage Out Objective Type Questions Question

Question 1.
Fill in the blanks:

1. Disposal of all types of solid wastes resulting in increasing …………………..
2. Domestic wastes is ………………….. wastes.
3. The wastes have different physical, chemical and ………………….. characteristics.
4. In vermicomposting ………………….. are added to the compost.
5. Open dump are not a good method of disposal of …………………..
6. Today ………………….. education is necessary in view of the crisis involves.
7. Paper can be recycled to get useful …………………..
8. All kinds of plastics give out harmful ………………….. upon heating or burning.

Answer:

1. Spoilage of land
2. Biodegradable
3. Biological
4. Earth worms
5. Wastes
6. Environmental
7. Products
8. Gases.

Question 2.
State whether the following statements are true (T) or false (F):

1. Wastes are the materials which are generally discarded by human beings.
2. The wastes generated in hospitals are non – hazardous in nature.
3. Organic waste is mostly biodegradable.
4. Organic matter can be decomposed and made into manure.
5. Open dump are a good method of disposal of wastes.
6. Polythene bags create a big problem in garbage disposal.
7. Garbage has both useful and non – useful components.
8. Waste is a uniform material in terms of its constituents.

Answer:

1. True
2. False
3. True
4. True
5. False
6. True
7. True
8. False.

Garbage In, Garbage Out Very Short Answer Type Questions 

Question 1.
What type of garbage are used for composting?
Answer:
Garbage of air kitchen like vegetable peels, egg cells, fruits peels and waste food are used for composting.

Question 2.
What type of garbage are not used for composting?
Answer:
Garbage like broken glass, old shoes, polythene bags, aluminium wrappers are not used for composting.

Question 3.
Should we burn the dried leaves?
Answer:
No.

Question 4.
How redworms grind the food?
Answer:
Redworms do not have teeth for grinding food. They have a structure called gizzards for grinding their food.

Question 5.
Can you recycle paper?
Answer:
Yes.

Question 6.
Can you recycle polythene?
Answer:
Some kind of plastics can be recycled, but not all of them.

Question 7.
List some items, we use, that are made of plastic.
Answer:
Combs, Toys, Shoes, Bags, Pens, Buckets, Bottles, Tooth brushes and Water pipes, etc.

Question 8.
Define land fill?
Answer:
Safai Karmcharis collect the garbage in trucks and take it to a low lying open area, called a landfill.

Question 9.
Who collects the garbage?
Answer:
Safai Karmacharis.

Question 10.
Name a few items that we throw as garbage almost everyday?
Answer:
Tins, paper, wrappers, plastic bags and peels of fruits, etc.

Question 11.
Define garbage?
Answer:
Any materials which is discarded by us or which is of no use for us is called garbage.

Question 12.
Define composting?
Answer:
The rotting and conversion of some materials into manure is called composting.

Question 13.
Define vermicomposting?
Answer:
The method of preparing compost with the help of redworms is called vermicomposting.

Question 14.
What is domestic wastes?
Answer:
The wastes include garbage, kitchen waste and sewage are called domestic wastes.

Garbage In, Garbage Out Short Answer Questions

Question 1.
In how many group we can group the garbage of our house?
Answer:
We separate the garbage of our house into two groups. These are:

Group 1:
Garbage from the kitchen like fruit and vegetable peels, egg shells, waste food, tea leaves. Include newspapers, dry leaves and paper bags in this group.

Group 2:
Piece of cloth, polythene bags, broken glass, aluminium wrappers, nails, old shoes and broken toys.

Question 2.
Why is it not advised to burn the dried leaves and husk?
Answer:
Burning of dried leaves, husk and part of some crop plants produces smoke and gases that are harmful to our health. So we should try to stop such practices and convert these wastes into useful compost.

Question 3.
List the various steps practiced in waste management?
Answer:
Various steps practiced in waste management are broadly divided into four steps:

1. Collection of wastes
2. Segregation of wastes
3. Reduction and resource recovery
4. Treatment and disposal.

Question 4.
Why earthworms are called farmer’s friends?
Answer:
Earthwarms are called farmer’s friends because they help to increase the fertility of soil. They eat dust and make soil fertile. They are used to perpare vermicompost, which gives many nutrients to soil and ultimately to crop plants.

Question 5.
Why plastic bags are harmful to us?
Answer:
The plastic bags thrown away carelessly on roads and other places get into drains and the sewer system. As a result, drains get choked and the water spills on the roads. During heavy rains, it might even create a flood like situation. There is a lot of harm that too much use of plastics can do.

Also, people fill garbage in plastic bags and then throw it on road. When stray animals looks for food in these bags, they end up swallowing these. Sometimes, they die due to this.

Garbage In, Garbage Out Long Answer Type Questions

Question 1.
Why is it necessary for us to separate waste into two separate dustbins provided by municipalities?
Answer:
In some cities and towns municipalities provide separate dustbins for collecting two kinds of garbage. Usually one is coloured blue and the other green. The blue bin is for materials that can be used again such as plastics, metals and glass. The green bins are for collecting kitchen and other plant or animal wastes. You may have noticed that this type of wastes rot completely when buried in the soil.

Question 2.
How recycling of paper is done?
Answer:
Tear the paper into small pieces. Put them in a tube or a bucket and pour water in it. Let the pieces of paper remain submerged in water for a day. Make a thick paste of paper by pounding it. Now, spread the wet paste on the wire mesh fixed to the frame. Pat it gently to make the thickness of layer of the paste as uniform as possible. Wait till water drain off. If required spread an cld cloth or a sheet of newspaper on the paste to let it soak up the extra water.

Now, carefully remove the layer of paste from the frame, spread it on a sheet of newspaper in the sun. Keep the corners of the newspaper sheet pressed by putting some weights to that these do not curl up. We can add food colour, pieces of dry leaves or flower petals or pieces of coloured paper in the paste before spreading it. It would help us to get a recycled paper with beautiful patterns on it.

Question 3.
What can we do to minimise over use of plastics and deal with garbage?
Answer:

1. We make a minimum use of plastic bags. We re – use the bags whenever it is possible to do so without any adverse affects.
2. We do not use plastic bags to store eatables.
3. We do not throw plastic bags here and there, after use.
4. We insist shopkeepers use paper bags. We carry a cloth or a jute bag when we go out for shopping.
5. We do not put garbage in plastic bags and throw it away.
6. We never burn plastic bags and other plastic items.
7. We recycle paper.
8. We use both sides of the paper to write. We use a slate for rough work. We use blank sheets of paper left in our notebooks for rough work.
9. We use vermicomposting at home and deal with our kitchen waste usefully.
10. We make our family, friends and others to follow proper practices for disposing different kinds of wastes.

The most important point to know and think about it that more garbage we generate, more difficult it will be to get rid of it.

MP Board Class 6th Science Solutions

 

 

MP Board Class 6th Science Solutions Chapter 15 Air Around Us

Air Around Us Textbook Exercises

Question 1.
What is the composition of air?
Answer:
The composition of air is:

• Nitrogen: 78.08%
• Oxygen: 20.95%
• Carbon dioxide: 0.034%
• Argon: 0.93%
• Helium: traces
• Water vapours: Traces

Thus, we see that air contains mostly nitrogen and oxygen. From above, it is clear that these two geses together make up 98% of the air.

Question 2.
Which gas in the atmosphere is essential for respiration?
Answer:
Oxygen gas in the atmosphere is essential for respiration.

Question 3.
How will you prove that air supports burning?
Answer:
This can be shown by following experiment:
Take a candle. Fix it on a table. Now light it. It starts burning. Then cover it with a glass cover so that all air supply is stopped. We will see that it stops burning after some time. As soon as air inside the glass is used up, the candle stops burning. This shows that air is necessary for burning.

Question 4.
How will you show that air is dissolved in water?
Answer:
Take some water in a glass vessel or beaker. Heat it slowly on a tripod stand. We see that tiny bubbles are sticking on it. These bubbles came from the air dissolved in water. When we heat water, the air dissolved in water escapes out in the form of bubbles. This shows that air is dissolved in water.

Question 5.
Why does a lump of cotton wool shrink in water?
Answer:
A lump of cotton wool shrink in water because the air inside cotton wool is driven out by water. They layers stick together and hence the lump of cotton wool shrinks.

Question 6.
The layer of air around the earth is known as?
Answer:
Atmosphere.

Question 7.
The components of air used by green plants to make their food, is?
Answer:
Carbon – dioxide.

Question 8.
List five activities that are possible due to the presence of air.
Answer:
The some activities that are possible due to the presence of air:

1. Windmill
2. Winnowing
3. Respiration
4. Flying of aeroplanes, birds, etc.
5. Transpiration.

Question 9.
How do plants and animals help each other in the exchange of gases in the atmosphere?
Answer:
Plants use carbon – dioxide to make their food and give out oxygen. The animals take oxygen for respiration and give out carbon – dioxide. This makes the balance of oxygen and carbon – dioxide in atmosphere. But if the green plants do not take in carbon – dioxide and give out oxygen, after some times there will no more oxygen on the earth and all living beings will die. That means, say, no life on earth. Thus, we can say that plants and animals help each other in the exchange of gases in the atmosphere.

Air Around Us Text Book Questions

Question 1.
Boojho is asking you, why do you think, the policeman in figure is wearing a mask?

Answer:
Policemen is wearing a mask to save his mouth and nose from dust particles and smoke due to the fuel burning in vehicles.

Question 2.
Paheli wants to know, why the transparent glass of windows, if not wiped off regularly, appears hazy?
Answer:
The transparent glass of windows wiped off regularly because the dust particles settle down on the glass.

Question 3.
Boojho want to know, why during an incident of fire, one is advised to wrap a woollen blanket over a burning object.
Answer:
Woollen blanket do not pass oxygen which supports burning. Hence, the burning will stop.

Question 4.
Here is a question from Paheli, “Will the tiny air bubbles seen before the water actually boils, also appear if we do this activity by reheating boiled water kept in an air tight bottle?” If you do not know the answer you may try doing it and see for yourself.
Answer:
No, in this case tiny air bubbles will not seen before the water actually boils.

Air Around Us Additional Important Questions

Air Around Us Objective Type Questions

Question 1.
Chose the correct answer:

Question (i)
Which of the following gases is not found free in air –
(a) Oxygen
(b) Nitrogen
(c) Hydrogen
(d) Carbondioxide.
Answer:
(c) Hydrogen

Question (ii)
The most abundant constituent of air is –
(a) Nitrogen
(b) Oxygen
(c) Carbondioxide
(d) Water vapour.
Answer:
(a) Nitrogen

Question (iii)
The percentage of oxygen by weight in the air is about –
(a) 78%
(b) 21%
(c) 23%
(d) 19%
Answer:
(b) 21%

Question (iv)
Air is –
(a) A compound
(b) A mixture
(c) An element
(d) An electrolyte.
Answer:
(b) A mixture

Question (v)
The constituent of air that is essential for life but does not support combustion is –
(a) Nitrogen
(b) Oxygen
(c) Carbondioxide
(d) Water vapor.
Answer:
(a) Nitrogen

Question 2.
Fill in the Blanks:

1. The cover of air around the earth is called ……………….
2. Air occupies ………………. and has
3. Air is ………………. of gases.
4. The major components of air are ………………. and ……………….
5. Air is a ………………. of gases.
6. Lime water is ………………. dissolved in water.
7. Lime water turns ………………. when carbon – dioxide is passed through it.
8. Carbon – dioxide is formed when is burned.
9. Candle burns in the atmosphere due to ……………….
10. ………………. does not support burning.

Answer:

1. Atmosphere
2. Space, mass
3. Mixture
4. Nitrogen, oxygen
5. Mixture
6. Lime
7. Milky
8. Fuel
9. Oxygen
10. Nitrogen.

Question 3.
Which of the following statements are true (T) or false (F):

1. Air is necessary for burning.
2. Air helps in dispersal of seeds.
3. Compressed air is used in the break system for stopping trains.
4. Fan circulates the air.
5. Birds can fly without air.
6. Air helps in pollination of seeds.
7. Animals can prepare food by photosynthesis.
8. Fishes can even breathe in water.
9. Plants do not use oxygen.
10. Oxygen is less on mountains.
11. Patients get oxygen from clyinders in case of any breathing problem.
12. Wind energy can be harnessed by a wind mill.

Answer:

1. True
2. True
3. True
4. True
5. False
6. True
7. False
8. True
9. False
10. True
11. True
12. True.

Question 4.
Match the items in Column A with the Column B:

Answer:

(i) (e)
(ii) (c)
(iii) (a)
(iv) (b)
(u) (d).

Air Around Us Very Short Answer Type Questions

Question 1.
What is air ?
Answer:
Air is gaseous substance.

Question 2.
What is atmosphere?
Answer:
The cover of air all around earth is called atmosphere.

Question 3.
What is the height of atmosphere above earth?
Answer:
Height of atmosphere is many hundred km above earth surface.

Question 4.
What is the height of clouds?
Answer:
Clouds are about 16 km above the earth surface.

Question 5.
When there is no food in your lunch – box, what is present in it?
Answer:
Only air is present.

Question 6.
Can you compress air?
Answer:
Yes, we can compress air. When we fill football with air we compress air.

Question 7.
At what height, generally the jet planes fly?
Answer:
Jet planes fly above clouds that mean at the height of more than 16 km from earth surface.

Question 8.
Name the components of air?
Answer:
Components of air are:

1. Oxygen
2. Nitrogen
3. Carbon – dioxide
4. Water vapours and
5. Dust particles.

Question 9.
What percentage of notrogen is present in air?
Answer:
Nearly 78% of air is nitrogen.

Question 10.
Which gas of air we use during respiration?
Answer:
Oxygen is used during respiration.

Question 11.
Give some examples where carbon dioxide is formed.
Answer:
Carbon – dioxide is formed when

1. Fuel burns,
2. Animals respire.

Question 12.
Who established for the first time that air contains more than one gases?
Answer:
The French scientist, Antoine Laurent Lovoisier in 1789.

Question 13.
Which gas is necessary for all living organisms?
Answer:
Oxygen.

Question 14.
How do fish respire in water?
Answer:
The fish take dissolved oxygen from water for respiration.

Question 15.
Which gas is given out during photosynthesis?
Answer:
Oxygen.

Question 16.
What is respiration?
Answer:
In respiration oxygen is taken up by all living organisms and used to break down food to give carbon – dioxide and energy.

Question 17.
How much air does a person take in per day?
Answer:
16 kg of air per day.

Question 18.
How does the air reduce harmful effects of smoke?
Answer:
Air spreads the smoke to a large area. Thus the smoke layer becomes thin and its harmful effect is decreased.

Question 19.
Why do clothes dry faster in wind?
Answer:
Rate of evaporation increases in wind and thus clothes dry faster in wind.

Question 20.
Why do we have gaps in firewood chulha?
Answer:
These gaps make air available all around the wood for continuous burning.

Question 21.
Why do factories have chimneys?
Answer:
Chimneys take smoke to a height. Air speeds is all over and effect of smoke decreases.

Question 22.
Why does a man sitting under a fan feel cooler?
Answer:
Fan circualtes the air and makes the evaporation of sweat rapid. Evaporation causes cooling and thus man feels cooler.

Question 23.
Why do we fill compressed air in tyres?
Answer:
Such tyres make transport smooth and easier.

Question 24.
What makes air impure?
Answer:
The presence of dust particles, dirt, increase percentage of carbon-dioxide, sulphur dioxide and smoke make the air impure.

Question 25.
Mention three objects which are inflated by air and are used commonly.
Answer:
Following objects are inflated by air:

1. Tyres of vehicles
2. Balloons
3. Footballs.

Air Around Us Short Answer Type Questions

Question 1.
Mentions five uses of air.
Answer:
Uses of air are:

1. All living things use air for respiration.
2. Air is necessary for burning.
3. Air is necessary for decay of waste material.
4. Air can be used to produce energy by wind mill.
5. Air helps in the dispersal of seeds from one place to other place.

Question 2.
Define a wheather cock.
Answer:
A wheather cock is a device which shows the direction of flow of air at that place.

Question 3.
What is photosynthesis?
Answer:
Process of making food by the green leaves of plant with the help of carbon – dioxide, water and sunlight is known as photosynthesis.

Question 4.
Who maintains the balance of oxygen and carbon – dioxide in nature?
Answer:
Plants and animals maintain the balance of oxygen and carbon – dioxide in nature. It follows as:

1. We breathe in oxygen and breathe out carbon – dioxide.
2. Plants use up carbon-dioxide when they produce food and oxygen.
3. Plants also use oxygen but they produce more than they use.

Question 5.
How will you show that air is a matter?
Answer:
To show that air is a matter, we have to show that air occupies space and air has mass. Take a balloon. Blow air in it. The size of ballon increases. This shows that air occupies space. Take another balloon. Weight it empty. Then fill it with air. Again weight. We will see after filling air the weight of balloon is more. This shows that air has mass. These two experiments show that air is a matter.

Question 6.
How will you show the presence of carbon – dioxide in air?
Answer:
Take a bottle filled with lime water. Then blow air from your mouth with the help of a pipe. The lime water will turn milky after some time. The carbon – dioxide present in air (from mouth) makes the lime water milky. This shows that carbon-dioxide is present in air.

Question 7.
When you finish your work in a laboratory you put the lid back on the spirit lamp. What happens then? Why?
Answer:
When we put the lid back on the spirit lamp it stops burning because on putting the lid air does not reach to lamp. It thus puts out spirit lamp.

Question 8.
Why do mountaineers and divers carry oxygen cylinders with them?
Answer:
At high altitudes on the mountains and deep in the sea the oxygen becomes very less. Due to less oxygen breathing becomes difficult. So mountaineers and divers carry oxygen cylinder with them.

Question 9.
Plants use carbon – dioxide for making their food. Where does this carbon – dioxide come from in the atmosphere?
Answer:
Plants use carbon – dioxide for making their food. But animals use oxygen for respiration and gives out carbon – dioxide. So this makes the balance of oxygen and carbon – dioxide in atmosphere.

Question 10.
How will you show that air is present in a lump of soil?
Answer:
The presence of air in a lump of soil can be shown by following experiment:
Take a lump of soil and put it into a plastic trough, half filled with water. We will see the bubbles of air coming out. These bubbles show that air is present in the lump of soil.

Question 11.
When you set fire to pieces of paper, it burns well. But when you set fire to a crumpled ball of paper, it burns only at the edge. Why is it so?
Answer:
Air is essential for burning. A piece of paper burns easily because it gets good supply of air. But in a crumbled ball of paper, it burns only at the edge. The inner layer does not get air.

Question 12.
Discuss the role of plants in the environment?
Answer:

1. Plants maintain balance between carbon – dioxide and oxygen in the atmosphere.
2. They act as noise and light filters.
3. They tend to lower down the atmosphere.

Question 13.
Draw a pie diagram showing the composition of air?

Air Around Us Long Answer Type Questions

Question 1.
How will you show that an empty bottle is filled with air?
Answer:
We perform the following experiment to show that empty bottle is filled with air:
Take a glass trough. Fill half of it with water. Introduce an inverted glass bottle into the water. We will see that water does not enter it. Now tilt the bottle slightly. We will find that bubbles of air escape through water and water starts filling in the bottle. This shows that water in the bottle is filled only when air comes out of bottle. This shown that even empty bottle is filled with air.

Question 2.
How will you show that air contains water vapours?
Answer:
Air has water vapours. It can be shown by following experiment:
Take half glass of water. Then add five pieces of ice in it. After some time we will see some water drops on outside surface of the glass.

These water drops have come by the condensation of water vapours present in air. This shows that air contains water vapours.

Question 3.
Explain wind mill with neat diagram?
Answer:
The wind makes the windmill rotate. The windmill is used to draw water from tubewells and to run flour mills. Windmils are also used to generate electricity. Air helps in the movements of sailing yachts, gliders, parachutes and aeroplanes. Birds, bats and insects can fly due to the presence of air. Air also helps in the dispersal of seeds and pollen of flowers of several plants. Air plays an important role in water cycle.

MP Board Class 6th Science Solutions

 

MP Board Class 6th Science Solutions Chapter 14 Water

Water Textbook Exercises

Question 1.
Fill in the blanks in the following:

1. The process of changing of water into its vapour is called ……………….
2. The process of changing water vapour into water is called ………………
3. No rainfall for a year or more may lead to ……………… in that region.
4. Excessive rains may cause ………………..

Answer:

1. Evaporation
2. Condensation
3. Draught
4. Flood.

Question 2.
State for each of the following whether it is due to evaporation or condensation:

1. Water drops appear on the outer surface of a glass containing cold water.
2. Steam rising from wet clothes while they are ironed.
3. Fog appearing on a cold winter morning.
4. Blackboard dries up after wiping it.
5. Steam rising from a.hot girdle when water is sprinkled on it.

Answer:

1. Condensation
2. Evaporation
3. Condensation
4. Evaporation
5. Evaporation.

Question 3.
Which of the following statements are “true”?

1. Water vapoure is present in air only during the monsoon.
2. Water evaporates into air from oceans, rivers and lakes but not from the soil.
3. The process of water changing into its vapour, is called evaporation.
4. The evaporation of water takes place only in sunlight.
5. Water vapour condenses to form tiny droplets of water in the upper layers of air where it is cooler.

Answer:

1. False
2. False
3. True
4. True
5. True.

Question 4.
Suppose you want to dry your school uniform quickly. Would spreading it near and anghiti or heater help? If yes, how?
Answer:
Yes, if we want to dry our school uniform quickly, we should spread our clothes near a anghiti or heater. The reason is that near anghiti or heater, temperature is more so water evaporation from the clothes will be faster, hence the clothes dry quickly.

Question 5.
Take out a cooled bottle of water from refrigerator and keep it on a table. After some time you notice a puddle of water around it Why?
Answer:
When we keep a cooled bottle of water taking out from a refrigerator we notice some puddles of water around it. This is due to the water – vapour near the surrounding atmosphere, condenses and deposites around the cooled water bottle. Water vapour always remains in the atmosphere.

Question 6.
To clean their spectacles, people often breathe out on glasses to make them wet. Explain why the glasses become wet.
Answer:
When we breathe on the spectacles, water vapour comes out from our breathe, and they condenses into water droplets when they come in contact of glass, because the glasses are cooler that the water vapours. Hence, the glasses becomes wet due to water puddles.

Question 7.
How does clouds formed?
Answer:
There is a continuous evaporation of water from surfaces of sea, rivers, lakes, etc. As we go higher from the surface of the earth, it gets cooler. When the air moves up, it gets cooler and cooler.

At sufficient height, the air becomes so cool that the water vapour present in it condenses to form tiny drops of water called droplets. It is these tiny droplets that remain floating in air and appear to us clouds.

Question 8.
When does a drought occur?
Answer:
If it does not rain in a region for a year or more. The soil continues to lose water by evaporation and transpiration. Since it is not being brought back by rain, the soil becomes dry. The level of water in wells and in ponds of the region goes down and some of them may also became scarce. This may lead to drought.

Projects and Activities

Activity 1.
List all the activities for which you use water in a day?
Answer:

Activity 2.
Write a slogan of your own on the topic ‘save water”?
Answer:
“Save Every Drop of Water”.

Water Text Book Questions

Question 1.
Boojho wonders whether people living in different regions of our country get the same amount of water. Are there regions where people not get adequate amount of water? How do they manage?
Answer:
The people living in different areas or regions of our country do not get the same amount of water. There are so many places in Rajasthan, where people do not get adequate amount of water. They manage their needs by storing the water.

Question 2.
Paheli wants to tell you that about two glasses of water are required to produce each page of a book.
Answer:
Yes.

Question 3.
Boojho wants you to imagine a day in your life when water supply through taps is not available. So, you have to fetch it yourself from a far away place. Would you use the same amount of water as on any other day?
Answer:
No, on such a day we will use less amount of water.

Question 4.
Paheli has noticed dew on leaves of grass on winter mornings. Did you notice something similar on leaves or metal surfaces like iron grills and gates on a cold morning? Is this also due to condensation? Do you see this happening on hot summer mornings?
Answer:
Yes, it is due to condensation. This does not happening on hot summer mornings.

Question 5.
Boojho has noticed fog near the ground in winter mornings. He wonders if this is also condensation of water vapour near the ground. What do you think?
Answer:
Yes, it is condensation of water vapour near the ground.

Water Additional Important Questions

Water Objective Type Questions

Question 1.
Choose the correct answer:

Question (i)
Water is –
(a) A mixture
(b) A compound
(c) An element
(d) None of these.
Answer:
(b) A compound

Question (ii)
The purest form of natural water is –
(a) River
(b) Sea
(c) Rain
(d) Spring.
Answer:
(c) Rain

Question (iii)
Salinity of sea water is about –
(a) 1.5%
(b) 2.5%
(c) 15%
(d) none of these.
Answer:
(b) 2.5%

Question (iv)
The major source of water on the earth is –
(a) Ground water
(b) Rain water
(c) Sea water
(d) Surface water.
Answer:
(b) Rain water

Question (v)
Drinking water is known as –
(a) Soft water
(b)Hard water
(c) Fresh water
(d) Potable water.
Answer:
(d) Potable water.

Question 2.
Fill in the blanks –

1. Water is one of the basic constituents of all ………………… things.
2. Water is required in the home for …………………. and ……………………
3. ………………… is essential for germination of seeds.
4. Water is essential for all animals and ………………….
5. Electricity can be generated by ………………….
6. In cold countries ………………….. water is used to worm their houses.
7. A car radiator is filled with water to keep the engine …………………
8. Pure water has ……………….. taste.
9. When water is boiled it changes to …………………
10. The boiling point of water is ………………………

Answer:

1. Living
2. Drinking, washing, bathing
3. Water
4. Plants
5. Water
6. Hot
7. Cool
8. No
9. Vapours
10. 100°C.

Question 3.
Which of the following statements are true: (T) or false (F):

1. Water from all sources is fit for drinking.
2. Chemicals are added in water to kill the germs present in it.
3. Sea water is a saline water.
4. Rain water is present form of water.
5. Water obtained from different.sources have same taste.
6. Pure water is blue in colour.
7. Water dissolved many substances, therefore it is a good solvent.
8. Water cycle deals with the circulation of water on the earth.
9. Whole of rain water goes to sea.
10. Water cycle makes the balance of water on the earth.
11. In atmosphere, temperature decreases with height.
12. Rain forms due to evaporation of clouds.

Answer:

1. False
2. True
3. True
4. True
5. False
6. False
7. True
8. True
9. False
10. True
11. False
12. False.

Question 4.
Match the items in Column A with Column B:

Answer:

(i) (c)
(ii) (d)
(iii) (b)
(iv) (a).

Water Very Short Answer Type Questions

Question 1.
What part of earth is covered with water?
Answer:
Three – fourth of earth is covered with water.

Question 2.
How much water is present in a –

1. Tree
2. Man
3. Elephant

Answer:
They have following percentage of water:

1. Tree – 60%
2. Man – 70%
3. Elephant – 80%.

Question 3.
How does a plant get water for living?
Answer:
A plant gets water from soil through its roots.

Question 4.
How does a plant lose it extra water absorbed by roots?
Answer:
Leaves of a plant has tiny pores in it. It loses extra water through these tiny pores.

Question 5.
What is transpiration?
Answer:
Plants lose their extra water continuously from the tiny openings present in their leaves. This process is known as transpiration.

Question 6.
Mention three sources of water.
Answer:

1. River
2. Lakes
3. Springs.

Question 7.
Which is the largest sources of water on earth?
Answer:
The largest source of water is ocean.

Question 8.
What chemicals would you use to kill the germs present in water?
Answer:
Chlorine is added to water to kill the germs present in water.

Question 9.
What are the different methods to make water fit for use?
Answer:
Water can be made fit for use by the following methods:

1. Boiling
2. Filtering
3. Treating water with chemicals like chlorine.

Question 10.
What is the saline water?
Answer:
Water which contains large amount of dissolved salts is called saline water.

Question 11.
Is water obtained from pond or lake fit for drinking?
Answer:
No, water obtained from pond or lake is not always fit for drinking. It may contain some impurities.

Question 12.
Why can’t we use sea water for drinking?
Answer:
Sea water is salty and hence cannot be used at home and in agriculture.

Question 13.
State three physical properties of water?
Answer:
Water is colourlesss, odourless, tasteless and transparent liquid.

Question 14.
What do you mean by water cycle in nature?
Answer:
The change of water from one form to another over and over in makes the water cycle in nature.

Question 15.
Is water obtained from every source fit for drinking?
Answer:
No, it is not safe for drinking. Before drinking it should be purified.

Question 16.
Why should water be conserved?
Answer:
Water is a natural resource. Once it is polluted it is difficult and expensive to purify it. Therefore, it should not be wasted but conserved.

Question 17.
How does forest help us?
Answer:
Forests increase in rainfall which increases the water level in wells, lakes and rivers.

Question 18.
Which is the purest form water?
Answer:
Rain water is the purest form of water.

Question 19.
What problems are faced by the people in drought areas?
Answer:
In drought areas, people face many problems. It is difficult to get food and fodder. Animals and plants will die in the absence of water.

Question 20.
Why should we protect our forest and grow more trees?
Answer:
We should protect our forest and also grow more trees because they help in rainfall. They increase rainfall. So we should grow more trees.

Question 21.
Name two pollutants.
Answer:
Water pollutants are household waste and industrial waste like detergents, chemicals like nitrates, phosphates etc.

Water Short Answer Type Questions

Question 1.
Define ground water.
Answer:
The ground water is actually rain water which mainly comes from seepage of water accumulated under the ground. Rain water percolates into the soil and reaches under the ground where water quantity increases and air decreases. This reserve water under the ground is called ground water. Open wells are fed by ground water. Ground water is the source of many lakes as well The more land pumps or tubewells that are used in an area, the deeper we need to dig to find this ground water.

Question 2.
What makes the sea water so saline?
Answer:
Rivers flowing from different places bring water containing dissolved salts and minerals into the sea. Sea water is continuously evaporated by the heat of sun. This evaporated water forms clouds and again fall on the earth as rain. This rain water again dissolves salts into it and goes into the sea. Thus the amount of salts in sea water goes in increasing.

Question 3.
Why is the water cycle important?
Water cycle is important to us because of the following:

1. It restores the supply of water in nature.
2. It regulates the temperature of atmosphere.
3. It regulates the weather or reasons.

Question 4.
Mention five uses of water?
Water is useful in many ways like:

1. For drinking, washing, cooking and other household works.
2. It is used for generation of energy in dams.
3. It is used for irrigation of fields for proper crop yield.
4. It is used in industries.
5. It is used in car to cool radiators.

Question 5.
Why is conservation of water essential?
Answer:
Water is essential for life. There are many sources of water, but water obtained from these sources are not fit for drking. To make it safe for drinking, it has to undergo many methods of purification, which is a long process. So water must be conserved. It means, it should be carefully and economically used.

Water Long Answer Type Questions

Question 1.
How will you show that water is essential for the germination of seeds?
Answer:
The following experiment shows that the water is essential for the germination of seeds:
Take two petrydishes. Put some gram seeds (say 20) in both the dishes. Add some water in dish 1 and keep dish 2 dry. Keep them for 6 hours. Now remove the water and keep wet cotton wool in dish 1, and dish 2 should be remained as such. Keep them for two days. After two days we will see that only moist seeds have been germinated while dry seeds remain as such. This shows that water is essential for germination.

Question 2.
Briefly describe water cycle in nature.
Answer:
The change of water from one form to another over and over again makes the water cycle in nature. Water cycle involves evaporation, condensation and precipitation. The water from the surface of sea, river, lakes or ponds is evaporated in the form of water vapours. Water is also evaporated from the surface of plants as transpiration.

These vapours rise high up in air and condense in the form of clouds. When temperature is low, the water precipitates in the form of rain, hails or snow to restore the supply of water back to the earth to repeat the cycle.

Question 3.
How can water wastage be minimised?
Answer:
The water which is safe for drinking is not available in plenty. Thus everyone should make efforts to save water. We should also minimise the water pollution.
We can minimise water wastage by following methods:

1. Pollution of water at sources should be minimised.
2. By using water carefully.
3. By growing forest. It helps in more rainfall and hence the excess of water will be available.
4. More number of dams on rivers will also help in wastage of rain water.
5. Rain water may also be collected.

Question 4.
What if it rains heavily? Discuss a scene of a flood area?
Answer:
The time, duration and the amount of rainfall varies from place to place. In some parts of the world it rains throughout the year while there are places where it rains only for a few days.
In our country, most of the rainfall occurs during the monsoon season. Rains bring relief especially after hot summer days. The sowing of many crops depends on the arrival of monsoon.

However, excess of rainfall may lead to many problems [see figure (a)]. Heavy rains may lead to rise in the level of water in rivers, lakes and ponds. The water may then spread over large areas causing floods. The crops fields, forests, villages, and cities may get submerged by water [Fig. (b)]. In our country, floods cause extensive damage to crops, domestic animals, property and human life.

During floods, the animals living in the water also get carried away with the waters. They often get trapped on land areas and die when floodwater recedes. Rains also affect the animals living in the soil.

Question 5.
What is rain water harvesting? How is it done? Discuss any two techniques of rainwater harvesting.
Answer:
One way of increasing the availability of water is to collect rainwater and store it for later use. Collecting rainwater in this way is called rainwater harvesting. The basic idea behind rainwater harvesting is “Catch water where it falls”. It flows into the drains, isn’t it? From roads and buildings water goes to rivers or lakes, which could be far away. A lot of effort will then be required to get this water back into our homes as the water did not seep into the ground.

The two techniques of rainwater harvesting are:
1. Rooftop rainwater harvesting:
In this system the rainwater is collected from the rooftop to a storage tank, through pipes. This water may contain soil from the roof and need filtering before it is used. Instead of collecting rainwater in the tank, the pipes can go directly into a pit in the ground. This then seeps into the soil to recharge or refill the ground water.

2. Another option is to allow water to go into the ground directly from the roadside drains that collect rainwater.

MP Board Class 6th Science Solutions

MP Board Class 6th Science Solutions Chapter 13 Fun with Magnets

Fun with Magnets Textbook Exercises

Question 1.
Fill in the blanks in the following:

1. Artificial magnets are made in different shapes such as …………….. , …………….. and ……………..
2. The materials which are attracted towards a magnet are called ……………..
3. Paper is not a …………….. material.
4. In olden days, sailors used to find direction by suspending a piece of ……………..
5. A magnet always has …………….. poles.

Answer:

1. Bar magnet, horse – shoe magnet, cylindrical.
2. Magnetic material
3. Plastic,
4. Suspended magnet
5. Two.

Question 2.
State whether the following statements are True (T) or False (F):

1. A cylindrical magnet has only one pole.
2. Artificial magnets were discovered in Greece.
3. Similar poles of magnet repel each other.
4. Maximum iron filings stick in the middle of a bar magnet when it is brought near them.
5. Bar magnets always point towards North – South direction.
6. A compass can be used to find East – West direction at any place.
7. Rubber is a magnetic material.

Answer:

1. False
2. False
3. True
4. False
5. True
6. False
7. False.

Question 3.
It was observed that a pencil sharpener gets attracted by both the poles of a magnet although its body is made of plastic. Name a material that might have been used to make some part of it.
Answer:
Iron.

Question 4.
Column I shows different positions in which one pole of a magnet is placed near that of the other. Column II indicates the resulting action between them for each situation. Fill in the blanks.

Answer:

Question 5.
Write any two properties of a magnet.
Answer:
The properties of a magnet are:

1. It attracts the objects made of iron, cobalt and nickle.
2. When it is suspended freely then it stands always in North – South direction.

Question 6.
Where are poles of a bar magnet located?
Answer:
On the two ends of the bar magnet.

Question 7.
A bar magnet has no markings to indicate its poles. How would you find out near which end is its north pole located?
Answer:
Take a bar magnet. Put a mark on one of its ends for identification. Now, tie a thread at the middle of the magnet so that you may suspend it from a wooden stand [Fig.]. Make sure that the magnet can rotate freely. Let it come to rest. Mark two points on the ground to show the position of the ends of the magnet when it comes to rest. Draw a line joining the two points. This line shows the direction in which the magnet Was pointing in its position of rest. Now, rotate the magnet by gently pushing one end in any direction and let it come to rest. Again, mark the position of the two ends in its position of rest.

Rotate  the magnet in other directions and magnet always comes to rest note the final direction in which it in the same direction comes to rest. We find that a freely suspended bar magnet always comes to rest in a North –  South direction. The end of the magnet that points towards North is called its North seeking end or the North pole of the magnet.

Question 8.
You are given an iron strip. How will you make it into a magnet?
Answer:
Take the iron strip and place it on the table. Now take a bar magnet and place one of its poles near one edge of the bar of iron. Without lifting the bar magnet, move it along the length of the iron bar till you reach the other end. Now, lift the magnet and bring the pole (the same pole you started with) to the same point of the iron bar from which you began (fig.) Move the magnet again along the iron bar in the same direction as you did before.

Repeat this process about 30 – 40 times. Bring a pin or some iron filings near the iron bar to check whether it has become a magnet. If not, continue the process for some more time. Remember that, the pole of the magnet and the direction of its movement should not change. In this way, an iron strip can be converted into a magnet.

Question 9.
How is a compass used to find directions?
Answer:
Magnetic Compass.
Magnetic compass consists of a small magnetized needle which is enclosed in a small round box made of aluminium. The box consists of a small pointed vertical axis (pivot) on which the magnetized needle rotates freely. The aluminium box is covered by thin glass cover.

The magnetized needle rotates freely and points towards geographic north from which true north can be calculated. This magnetic compass is used to find the direction at any place. Sailors and navigators also use this compass to find the direction during their journey.

Question 10.
A magnet was brought from different directions towards a toy boat that has been floating in water in a tub. Affect observed in each case is stated in Column I. Possible reasons for the observed affects are mentioned in Column II. Match the statements given in Column I with those in the Column II

Answer:

(i) (d)
(ii) (e)
(iii) (b)
(iv) (a)
(v) (b).

Projects and Activities

Activity 1.
collect various objects of day – to – day use from your sourroundings. Test these with the “Magnes stick”. You can also take a magnet, touch these objects with it and observe which objects stick to the magnet. Prepare a table and record your observations.
Answer:
Table: Finding the objects attracted by magnet

Fun with Magnets Text Book Questions

Question 1.
Boojho has this question for you. A tailor n was stitching buttons on his Shirt. The needle has slipped from his hand on to the floor. Can you help the tailor to find the needle?
Answer:
Yes, with the help of magnet.

Question 2.
Paheli has this puzzle for you. You are given tow indentical bars which look as if they might be made of iron. One of them is a magnet, while the other is a simple iron bar. How will you find out, which one is a magnet?
Answer:
The magnet has two poles where attraction is maximum. But in iron bar there is no pole, so attraction is same everywhere.

Fun with Magnets Additional Important Questions

Fun with Magnets Objective Type Questions

Question 1.
Choose the correct answer:
Question (i)
North pole of a magnet –
(a) Attracts north pole
(b) Remains inactive
(c) May attract or repel
(d) Repels north pole.
Answer:
(d) Repels north pole.

Question (ii)
Which one is natural magnet –
(a) Ferrite
(b) Carbon
(c) Iron
(d) Magnetite.
Answer:
(b) Carbon

Question (iii)
Which of the following is non – magnetic –
(q) Iron
(b) Nickel
(c) Cobalt
(d) Aluminium.
Answer:
(d) Aluminium.

Question (iv)
An electrolyte is a –
(a) Solid that conducts electricity
(b) Liquid that does not conduct electricity
(c) Solid that does not conduct electricity
(d) Liquid that conducts electricity and breaks up chemically in the process.
Answer:
(d) Liquid that conducts electricity and breaks up chemically in the process.

Question (v)
Strength of a magnet is –
(а) Maximum at centre
(b) Maximum at poles
(c) Minimum at poles
(d) None of these.
Answer:
(а) Maximum at centre

Question 2.
Fill in the blanks:

1. Iron and nickle are …………….. materials whereas copper and aluminium are …………….. materials.
2. The regions of strongest magnetism in a magnet are known as the ………………
3. Like poles ………………. whereas unlike poles
4. The molecular magnets in a magnet are arranged in groups called ……………..
5. Steel is used to make …………….. magnets.
6. The shaving blade is an inexpensive ………………

Answer:

1. Magnetic, non – magnetic
2. Ends
3. Repel, attract
4. Domains
5. Permanent
6. Magnet.

Question 3.
Which of the following statements are true (T) false (F):

1. The magnetite is mainly composed of oxides of iron.
2. Like poles of a magnet attract each other,
3. Plastic is a non – magnetic material.
4. A magnet looses its magnetism on striking voilently with hammer.
5. Magnets point towards East – West when freely suspended.
6. Earth behaves like a huge magnet.
7. Orested a Danish scientist noticed that a compass needle was affected by the electric current flowing in the neighbouring coil of wire.
8. The most important property of magnet is to attract iron pieces.
9. A horse – shoe magnet.can have only one pole.
10. A magnet can have two north poles.

Answer:

1. True
2. False
3. True
4. False
5. True
6. True
7. True
8. Ture
9. False
10. False.

Question 4.
Match the items of Column A with Column B:

Answer:

(i) (b)
(ii) (c)
(iii) (d)
(iv) (a).

Fun with Magnets Very Short Answer Type Questions

Question 1.
When was magnetite discovered?
Answer:
Magnetite was discovered in 800 B. C.

Question 2.
From where a mineral magnetite was discovered first.
Answer:
It was discovered in the town of Magnesia.

Question 3.
Why was magnetite named Londestone?
Answer:
It was named so because this mineral can align itself in the same direction it left to rotate freely.

Question 4.
Which is the North Pole of a bar magnet?
Answer:
It is the tip of a bar magnet which points towards the north direction.

Question 5.
Which is the South Pole of a bar magnet?
Answer:
It is the tip of a bar magnet which points towards the south direction.

Question 6.
What is a temporary magnet?
Answer:
It is piece of magnet only for a short period. This magnetism is lost as soon as the source of magnetisation is removed.

Question 7.
How should we store magnets?
Answer:
We should store magnets by joining opposite poles of two magnets preferably with a piece of iron in between.

Question 8.
Who discovered the magnetic effects of electric current?
Answer:
Danish Scientist H. C. Uersted discovered the phenomenon in 1820.

Question 9.
What are domains?
Answer:
When we study a magnet in microscope, it consists of small regions. These regions are called domains.

Question 10.
How is magnet and electric current similar in property?
Answer:
Because wires having electric current behave like a magnet. In electric current also like charges repel and unlike charges attract

.

Question 11.
What is a magnetic needle?
Answer:
This needle moves a pivot fixed at the centre of a round frame box. It is used by navigators for finding out the direction in the sea.

Question 12.
Name some non-magnetic materials.
Answer:
Plastic, cloth, paper and leather, etc. are non – magnetic materials.

Question 13.
What are the ends of a magnet called?
Answer:
Poles.

Question 14.
What is natural magnet called?
Answer:
Magnetite.

Question 15.
Which iron is used for making a permanent magnet?
Answer:
Hard steel and alloys.

Question 16.
What is the instrument in which directive property of a magnet is used?
Answer:
Mariner’s compass.

Fun with Magnets Short Answer Type Questions

Question 1.
What is a magnet? How is a temporary magnet different from a permanent magnet?
Answer:
Any material that has the property of attracting iron is called a magnet.
Difference between temporary and permanent magnet:

Temporary magnet:

• It is magnet for a short period.
• Its magnetism is lost if source of magnetisation is removed.
• It is made up of soft iron.

Permanent magnet:

• It is magnet for ever.
• It remains magnet even if the source of magnetisation is removed.
• It is made up of steel.

Question 2.
Can you make out the south and north direction with the help of bar magnet. How?
Answer:
Yes, we can make out the south and north directions with the help of bar magnet. Suspend a magnet from a string tied to its middle so that it can rotate freely. The tip of the bar magnet which point north will rest to the north direction and the tip bearing south will rest to point towards south direction.

Question 3.
Define magnetism. Also give the name of magnetic and non – magnetic substance.
Answer:
Magnetism:
Magnet has the property of attracting various substances towards itself. This property of magnet is called magnetism.

Magnetic substances:
Those substances which are attracted by a magnet are called magnetic substances. For examples-, nickel, iron steel, cobalt and alloys of these substances are magnetic in nature.

Non – magnetic substances:
Those substances which are not attracted by a magnet are called non-magnetic substances. For examples, glass, cloth, wood, cloth, etc.

Question 4.
How can you make your personal compass?
Answer:
Magnetise an iron needle using a bar magnet. Now, insert the magnetised needle through a small piece of cork or foam. Let the cork float in water in a bowl or a tub. Make sure that the needle does not touch the water (Fig.). Your compass is now ready to work.

Question 5.
What is an electromagnet? Give two applications of electromagnets?
Answer:
When an electric current flows through a coil of wire, the coil behaves like a permanent magnet. When this current carrying coil is brought near a suspended bar magnet, one end of the coil repeals the north pole of the magnet. The other end of the coil attracts the north pole of the magnet. Thus, a current carrying coil has both a north and south pole like a magnet, such a magnet is called electromagnet.

Applications of electromagnet:

1. They are used in electric bells, telephones, telegraphps, etc.
2. They are used to separate magnetic substances like nickel, cobalt and iron from non – magnetic substances like brass, copper, zinc and plastics.

Fun with Magnets Long Answer Type Questions

Question 1.
What happens when the north pole of a magnet is brought near (i) the north pole, (ii) the south pole of a freely suspended magnet?

Answer:
Suspend a bar magnet with a string. This bar magnet should be marked with north and south pole.

1. Hold another magnet in hand and bring its north pole close to each pole one by one. North pole of two magnet will repel each other as they are like poles.
2. While north of magnet, in hand comes close to south of suspended magnet, it will show attraction because they are unlike poles.

Question 2.
Can we have an isolated north pole or south pole?
Answer:
An isolated magnetic pole is not possible. Two magnetic poles of a magnet cannot be separated.
If a magnet is broken into two pieces, each piece is a magnet having north and south pole. If these pieces are further broken into more smaller pieces, each piece consists the two poles (i.e., north pole and south pole) at its ends.

Dividing a magnet infinitely would still produce tiny magnets each having its own poles at two ends. This shows that two poles of a magnet cannot be separated and an isolated magnetic pole does not exist.

Question 3.
Explain the process by which a permanent magnet can magnetise an ordinary piece of iron?
Answer:
A piece of iron can be magnetised by two methods:

1. By single touch method. Put a piece of iron on the table:
Hold a bar magnet on it vertically with north pole touching. Now move the magnet along the length. By repeating this practice many times makes that iron piece a magnet.

2. By double touch method:
Put a piece of iron on the table. Hold two bar magnets on it vertically with north and south pole of two magnets. Put them in the middle first. Move the magnets in opposite direction as shown in figure. Repeating this process converts the piece of iron into a magnet.

Question 4.
Why does a freely suspended magnet always come to rest in the north – south direction?
Answer:
This is because the earth itself behaves like a huge bar magnet with its magnetic poles near the geographical north and south poles. The south pole of this bar magnet is near the geographical north pole, whereas the north pole of the bar magnet is near the geographical south pole.

In a freely suspended magnet, therefore, the north pole points towards the geographical north pole since it is attracted by the earth’s magnetic south pole. Similarly, the south pole of the suspended magnet is attracted by the earth’s magnetic north pole and, therefore, points towards the geographical south pole.

Question 5.
Write a short note on the cautions of magnets?
Answer:
Magnets loose their properties if they are heated, hammered or dropped from some height [Fig. (a)]. Also, magnets become weak if they are not stored properly.

To keep them safe, bar magnets should be kept in pairs with their unlike poles on the same side. They must be separated by a piece of wood while two pieces of soft iron should be placed across their ends [Fig. (b)]. For horse-shoe magnet, one should keep a piece of iron across the poles.

Keep magnets away from cassettes, mobiles, television, music system, compact disks (CDs) and the computer. [See Fig. (c)]

MP Board Class 6th Science Solutions

MP Board Class 6th Science Solutions Chapter 6 Changes Around Us

Changes Around Us Textbook Exercises

Question 1.
To walk through a waterlogged area, you usually shorten the length of your dress by folding it. Can this change be reversed?
Answer:
Yes, this change can be reversed.

Question 2.
You accidentally dropped your favourite toy and broke it This is a change you did not want Can this change be reversed?
Answer:
No, this charge can not be reversed.

Question 3.
Some changes are listed in the following table. For each change, write in the blank column, whether the change can be reversed or not?

Answer:

1. No
2. Yes
3. Yes
4. No
5. No
6. No.

Question 4.
A drawing sheet changes when you draw a picture on it. Can you reverse this change?
Answer:
If the picture is drawn with a pencil, then it can be erased, hence the change can be reversed. But if the picture is drawn with colours, the change cannot be reversed.

Question 5.
Give examples to explain the difference between changes that can or cannot be reversed?
Answer:
A change is said to be reversible or reversed when it can occur in both the forward and backward directions. For example, melting of ice in water and then its condensation into ice again; filling water with jug; opening or closing the door, etc. A change is said to be irreversible or cannot be reversed when it occurs only in one direction. For example, burning of match – stick repening of fruit; curdling of milk, etc.

Question 6.
A thick coating of a paste of Plaster of Paris (POP) is applied over the bandage on a fractured bone. It becomes hard on drying to keep the fractured bone immobilised. Can the change in POP be reversed?
Answer:
No, the change in POP cannot be reversed.

Question 7.
A bag of cement lying in the open gets wet due to rain during the night. The next day the sun shines brightly. Do you think the changes, which have occurred in the cement, could be reversed?
Answer:
No, the changes which have occurred in the cement cannot be reversed.

Projects and Activities

Activity 1.
Make a table to show some common changes?
Answer:
Some common changes

Question 2.
Paheli wants to know if you have ever seen a blacksmith making some tools. How does a blacksmith change a piece of iron into different tools? A piece of iron is heated till it becomes red – hot. It then becomes soft and is beaten into a desired shape. What change has taken place in iron, on being heated?
Answer:
Expansion.

Changes Around Us Additional Important Questions

Changes Around Us Objective Type Questions

Question 1.
Choose the correct answer:

Question (a)
Which of the following is not reversible change?
(а) Burning of a piece of paper
(b) Ploughing a field
(c) Pulling of rubber string
(d) Melting of wax.
Answer:
(а) Burning of a piece of paper

Question (b)
From the following which is an irreversible change?
(а) Leaves turn yellow:
(b) Falling of leaves from tree
(c) Leaves turn into manure
(d) All the above.
Answer:
(d) All the above.

Question (c)
Chemical changes are:
(a) Always reversible
(b) Sometimes reversible
(c) Irreversible
(d) None of these.
Answer:
(a) Always reversible

Question (d)
All chemical changes are necessarily:
(a) Irreversible
(b) Reversible
(c) Fast
(d) None of these.
Answer:
(v) None of these.

Question 2.
Fill in the blanks:

1. Changes that repeat after a certain interval of time are called ……………………..
2. Changes that lead to the formation of new substances are called ……………………………
3. Burning of wood in a chulha is a …………………….. change but forest fire is an
4. Melting of candle wax is a …………………….. change but its burning is a …………………….. change.
5. Energy is ……………………… in the formation of curd from milk.

Answer:

1. Periodic changes
2. Chemical changes
3. Desirable change, undesirable change
4. Physical, chemical
5. Liberated.

Question 3.
Which of the following statements are true (T) or false (F):

1. Cooking of rice is a physical change.
2. Breaking of a china dish is a chemical change.
3. Rusting of iron is an irreversible change.
4. Eruption of a volcano is a periodic change.
5. Formation of clouds is a fast change.

Answer:

1. False
2. False
3. True
4. False
5. False.

Question 4.
Match the items in Column A with items in Column B:

Answer:

Changes Around Us Very Short Answer Type Questions

Question 1.
Is picking of mango a desirable change? Why?
Answer:
Picking of mango is always a desirable change. We pickle mango according to our taste and desire.

Question 2.
Is printing a reversible or an irreversible change?
Answer:
Printing is irreversible change because printed matter cannot be easily erased.

Question 3.
Can you obtain wood from sawdust?
Answer:
We cannot obtain wood from sawdust because it is an irreversible change.

Question 4.
Why we classify the changes taking place around us?
Answer:
We classify the changes taking place around us to have better understanding of these changes. We classify changes according to the nature of the change.

Question 5.
What is a slow change? Give examples?
Answer:
A change which occurs slowly and completes in days, months or years is a slow change. For example, rusting of iron, change of seasons, ageing, growth of a tree, weathering of rocks, etc.

Question 6.
What is a fast change? Give examples?
Answer:
A change which occurs rapidly and completes in seconds or a minutes is a fast change. For example, breaking of glass tumbler, burning of a match – stick, beating of heart, explosion of a pracker, etc.

Question 7.
What change takes place when an iron rod is heated up and cooled down?
Answer:
It is an irreversible change.

Question 8.
Can we say that ironing of clothes is a reversible change? Answer with reason?
Answer:
Yes, in the sense that ironing of cloth does not make a permanent change in the cloth fibre yet we can say it may be called as an irreversible change because ironing affects the upper surface of cloth which is consumed.

Changes Around Us Short Answer Type Questions

Question 1.
What is a physical change? Give examples?
Answer:
A change is said to be a physical change when it involves the change only in the physical properties of a substance. The chemical properties are retained. For example, melting of ice, heating of water, moulding of clay, magnetization of iron piece, etc.

Question 2.
What is a chemical change? Give examples?
Answer:
A change is said to be a chemical change when it involves the change both in the physical and chemical properties of a substance. For example, curding of milk, burning of magnesium ribbon to form magnesium oxide, rusting of iron, to form oxide, burning of fuels to form ash and carbon dioxide, etc.

Question 3.
Formation of clouds is a physical change; Explain?
Answer:
The formation of clouds is a physical change because water from rivers, lakes or oceans evaporates, then it is converted into water vapours it is a temporary change. The change is reversible. There is no change in composition.

Question 4.
Explosion of a cracker is a chemical change. Explain?
Answer:
In the explosion of a cracker the mixture of sulphur, nitrate and other substances burn. There is an evolution of energy. The change is not reversible and the smoke and other gases cannot be converted back into the cracker.

Question 5.
Give two examples of changes in which energy is given out?
Answer:
The two examples of changes in which energy is given out are:

1. Burning of magnesium ribbon to form magnesium oxide.
2. Addition of sulphuric acid in water produce heat.

Question 6.
Give two examples of changes in which energy is absorbed?
Answer:
The two examples of changes in which energy is absorbed are:

1. Evaporation of alcohol.
2. Dissolution of ammonium chloride in water.

Question 7.
What are natural and man – made changes? Give examples?
Answer:
The changes which occurs in nature are called natural changes. For example, change of seasons, growth of child, germination of seed, weathering of rocks, flowering of plants, etc. The changes which do not occur in nature but are carried out including by man are called man – made changes. For example, burning of fuel, melting of wax, breaking of stones, making of ice – cream, etc.

Question 8.
Is burning always a desirable change? Explain?
Answer:
Burning of wood or coal in our homes is a desirable change as it is useful to us. Burning of wood or charcoal will become an undesirable change if burning of wood produces smoke and pollutes the air. Similarly burning of wood unnecessarily should be avoided as it is wastage of costly wood. Burning of petrol, kerosene oil is a source of pollution of air in cities.

Question 9.
Is falling of trees always an undesirable change? Give reasons?
Answer:
Falling of trees for making furniture or timber is a desirable change. Though falling of trees can be undesirable because forest wealth will be lost when falling of trees is taken on a large scale.

Question 10.
Sort out reversible changes from the following:

1. Melting of ice
2. Wheat turn into flour
3. Melting of wax
4. Making of ice – cream from milk
5. Growing old.

Answer:
Reversible changes are:

1. Melting of ice
2. Melting of wax.

Question 11.
Classify the following as physical or chemical changes:

1. Melting of glass
2. Burning of agarbatti
3. Tearing of cloth
4. Formation of seed from flower
5. Cooking of food
6. Formation of cloud.

Answer:
Physical change:

1. Melting of glass.
2. Tearing of cloth.
3. Cooking of food.

Chemical change:

1. Burning of agarbatti
2. Formation of seed from flower.
3. Formation of cloud.

Question 12.
Classify the following as reversible or irreversible changes:

1. Growth of a plant
2. Ploughing a field
3. Melting of wax
4. Falling of rain
5. Pulling of rubber string
6. Breaking of a glass rod
7. Cooking of food.

Answer:
Reversible change:

1. Ploughing a field
2. Melting of wax
3. Pulling of rubber string

Irreversible change:

1. Growth of a plant
2. Falling of rain
3. Breaking of glass rod
4. Cooking of food.

Question 13.
See the picture and tell, in the candle:

1. Which type of change is melting wax? Explain?
2. Which type of change is burning wax? Explain?

Answer:

1. The melting of wax is a physical change, because during this process of melting, it is changing into liquid state and after cooling down, again it becomes solid.
2. The burning of wax is a chemical change because when the cotton wick embeded in the candle is burnt, ash and smoke is formed. It is not possible to make a wick from this ash and smoke.

Question 14.
Most physical changes are reversible, give reasons?
Answer:
In physical changes there is no change in the composition of substances. There may be a change in size, shape of the substances where a physical change takes place. Hence it is possible to produce the reactants from the products easily. The physical changes are mostly reversible.

Changes Around Us Long Answer Type Questions

Question 1.
How metal rim is fixed on the wooden wheel of a cart?
Answer:
The metal rim is made slightly smaller than the wooden wheel. On heating, the rim expands and fits onto the wheel. Cold water is then pouted over the rim, which contracts and fits tightly onto the wheel.

Question 2.
How wooden handle is fixed in the ring of the iron tool?
Answer:
The iron blade of these tools has a ring in which the wooden handle is fixed. Normally, the ring is slightly. smaller in sir e than the wooden handles fix the handle the ring is heated and it becomes slightly larger in size (expands) Now, the handle easily fits into the ring. When the ring cools down it contracts and fits tightly on to the handle.

Question 3.
Give reason of:

1. Rotation of fan is a periodic change.
2. Rusting of iron is a chemical change.
3. Ripening of fruit is an irreversible change.

Answer:

1. Rotation of fan involves the movement of the blade, takes place at a fixed speed This movement is repeated after definite interval, hence the rotation of fan is a periodic change.

2. Rusting of iron is a chemical change because when the iron comes in contact with moist air, then it reacts with oxygen present in the air and starts rusting. Rusting of iron cannot be changed back into pure iron.

3. Ripening of fruit produces a change in the composition of the fruit. Ripened fruit cannot be changed back into the unripened fruit. It is an irreversible change. Hence this change is a chemical change.

Question 4.
What are desirable and undesirable changes? Give example?
Answer:
The changes which are useful to us are desirable changes. The changes which are not useful to us are called undesirable changes. We like the desirable changes to happen again but not the undesirable changes. The desirable changes include growth of a tree, undesirable changes. The desirable changes include growth of a tree, flowering of a plant, germination of seeds, formation of manure from cow – dung etc. The undesirable changes include breaking of glass tumbler, rusting of iron, rottening of food – stuffs, etc.

Question 5.
Give two examples of changes which are both desirable and undesirable?
Answer:

1. The burning of fuels like wood, coal or petrol is both desirable and undesirable change. The burning of fuels produce heat which is desirable but the burning also produce smoke. It pollutes the atmosphere and is undesirable.

2. The cutting of tree for wood is both desirable and undesirable change. The cutting provides wood for making furniture is desirable. At the same time the cutting of tree is undesirable because it destroys the natural balance.

Question 6.
Mention any three undesirable changes from your daily life?
Answer:
The three undesirable changes are:

1. The burning of wood because on burning wood produces ash and smoke. Ash pollutes water and land, and smoke pollutes air.
2. Rottening of food – stuff by bacteria or fungi. It spoils the food and makes it undesirable for eating purposes.
3. Rusting of iron because iron after rusting corrodes and cannot be welded.

Question 7.
Differential between physical and chemical change?
Physical change:

1. It involves change in the physical properties.
2. It is temporary.
3. It does not involve formation of new substance.
4. It does not involve any energy change is substance.

Chemical change:

1. It involves change both in the physical and chemical properties.
2. It is permanent.
3. It involves the formation of new substance.
4. It involves energy changes as the chemical reactions are either exothermic or endothermic.

Question 8.
Classify the following changes in as many ways as you can:

1. Breaking of a brick with hammer.
2. Beating of heart.
3. Germination of seed.
4. Burning of an incense stick (agarbatti).
5. Occurrence of solar eclipse.

Answer:

1. Breaking of a brick with hammer is a fast, irreversible, undesirable, unperiodic and a physical change.
2. Beating of heart is slow, periodic, irreversible and a desirable change.
3. Germination of seed is slow, irreversible, unperiodic, desirable and a chemical change.
4. Burning of an incense stick (agarbatti) is a slow, irreversible, desirable, periodic and a chemical change.
5. Occurrence of solar eclipse is a non – periodic, an irreversible and a physical change.

Question 9.
State the criterion/reason for each of the following:

1. Cooked food is stored in a refrigerator,
2. Iron sheet is coated with tin before making a can,
3. Common salt is stored in ari airtight container during the rainy season?

Answer:

1. Cooked food is stored in a refrigerator to prevent it from rotting. In the refrigerator the temperature of the food is lowered and degeneration of food material does not take place. It remains worth eating for many days. It gets preserved.

2. Iron sheet is coated with tin before making a can because coating with tin projects iron from rusting. This protects the can and it can be used for a longer time than the can which is not coated with any protecting metal.

3. Common salt is a substance which absorb water from the atmosphere. It gets wet and corrodes the container made of iron or aluminium. To prevent the absorption of water by the common salt we have to store it in an air it tight container during rainy season.

Question 10.
Choose appropriate alternative and give reason for your choice in the following statements?

1. Occurrence of an eclipse of moon is a periodic/non – periodic change.
2. Catching cold is a periodic change/non-periodic change.
3. Arrival of a comet is a periodic/non-periodic change.

Answer:

1. Occurrence of eclipse of moon takes place when moving earth comes in between the sun and the moon is a non – periodic change because eclipses of the moon do not occur after specific intervals.
2. Catching cold is not a periodic change because it is not at all necessary that common cold may inflict a person at specific intervals of time.
3. Arrival of comet is also a non – periodic change because comets do not arise after specific time. They form occasionally and may not occur for many years.

MP Board Class 6th Science Solutions

MP Board Class 6th Science Solutions Chapter 11 Light, Shadows and Reflections

Light, Shadows and Reflections Textbook Exercises

Question 1.
Rearrange the boxes given below to make a sentence that helps us understand opaque objects?

Answer:

Question 2.
Classify the objects or materials given below as opaque, transparent or translucent and luminous or non -luminous? Air, water, a piece of rock, a sheet of aluminium, a mirror, a wooden board, a sheet of polythene, a CD, smoke, a sheet of plane glass, fog, a piece of red hot iron, an umbrella, a lighted fluorescent tube, a wall, a sheet of carbon paper, the flame of a gas burner, a sheet of cardboard, a lighted torch, a sheet of cellophane, a wire mesh, kerosene stove, sun, firefly, moon.
Answer:
Obaque objects:
A piece of rock, a sheet of aluminium, a mirror, a wooden board, a CD, a wall, a sheet of cardboard.

Transparent objects:
Air, water, sheet of plane glass.

Translucent objects:
A sheet of polythene, smoke, fog, a sheet of carbon paper, a sheet of cellophone.

Luminous objects:
A piece of red hot iron, a lighted fluorscent tube, the flame of a gas burner, a lighted torch, sun, firefly, kerosene stove.

Non – luminous Objects:
An umberela, a wire mesh, moon.

Question 3.
Can you think of creating a shape that would give a circular shadow if held in one way and a rectangular shadow if held in another way?
Answer:
Yes, we can think of creating a shape that would give a circular shadow if held in one way and a rectangular shadow of held in another way.

Question 4.
In a completely dark room, if you hold up a mirror in front of you, will you see a reflection of yourself in the mirror?
Answer:
No, in a completely dark room, we cannot see our right – left inverted image in the mirror, because there is no source of light.

Projects and Activities:

Activity 1.
Look around you and collect as many objects as you can an eraser, plastic scale, pen, pencil, notebook, single sheet of paper, tracing paper or a piece of cloth. Try to look at something far away, through each of these objects. Is light from a far away object able to travel to your eye, through any of the objects?
Record your observations in a table.
Answer:

Activity 2.
Describe an experiment which shows that light propagates in a straight line?
Answer:
In a homogeneous medium, light travels in a straight line path. This is called rectilinear propagation of light. This can be demonstrated with the help of three card – board pieces A, B and C with a fine hole at their centres. A candle or a bulb is placed on one side and the boards are arranged such that the holes are in straight lines as shown in figure. Looking from the other side, it is found that the fight from the candle is received only when the three holes are in a straight fine. If one of the card board pieces is displaced, the fight is no longer seen. This clearly demonstrates that the fight travels in a straight fine path.

Things to Think About:

Question 1.
Opaque objects cast shadows, isn’t it? Now, if we hold a transparent object in the Sun, do we see anything on the ground that gives us a hint that we are holding something in our hand?
Answer:
Yes, it gives us a fuzzy shadow on the ground, which gives us a hint that we are holding some thing in our hand.

Question 2.
We saw that changing colour of opaque objects does not change the colour of their shadows. What happens if we place an opaque object in coloured light? You can cover the face of a torch with a coloured transparent paper to do this. (Did you ever noticed the colours of evening shadows just as the Sun is setting?)
Answer:
Yes, the colour of shadow depends upon the colour of the objects. If we can change the colour of opaque objects, the same colour will be seen in shadow.

Light, Shadows and Reflections Additional Important Questions

Light, Shadows and Reflections Objective Type Questions

Question 1.
Choose the correct answer:

Question (i)
A pinhole camera forms an image of a building on its screen. Compared to the building, its image would be –
(а) Larger and inverted
(b) Larger and upright
(c) Smaller and inverted
(d) Smaller and upright.
Answer:
(c) Smaller and inverted

Question (ii)
The transparent object out of the following is –
(a) Water
(b) Moon
(c) Rubber sheet
(d) None of these
Answer:
(a) Water

Question (iii)
Which of the following objects allow more light to pass through –
(a) Translucent
(b) Opaque
(c) Transparent
(d) None of these.
Answer:
(a) Translucent

Question (iv)
The objects which do not allow the light to pass through them at all are called –
(a) Opaque
(b) Translucent
(c) Transparent
(d) None of these.
Answer:
(a) Opaque

Question (v)
In a room lighted by an electric bulb, it is found that the shadow of the ceiling fan hung in the centre is falling on a wall opposite to the door. What can you say about the position of the bulb –
(a) On the wall on your right as you enter the room.
(b) On the wall on your left as you enter the room.
(c) On the wall facing the door.
(d) On the wall on which the door is fixed.
Answer:
(b) On the wall on your left as you enter the room.

Question 2.
Fill in the blanks:

1. Opaque objects cast shadow.
2. The shadow is longest during and
3. The totally dark portion of a shadow is called
4. Surfaces act like mirrors.
5. Solar eclipse occurs only on moon days.
6. Lunar eclipse occurs only on moon days.
7. A pin – hole camera is based on propagation of light.
8. Surfaces act like mirrors.

Answer:

1. Dark
2. Sunset, sunrise
3. Umbra
4. Polished,
5. New
6. Full
7. Straight
8. Luminous.

Question 3.
Which of the following statements are true (T) or false (F):

1. A fire fly is a hot source of fight.
2. The sun is a natural source of fight.
3. The tourch is a man – made source of fight.
4. The partially dark portion of a shadow is called umbra.
5. Formation of a sharp shadow of an object in sunlight is an evidence of the rectilinear propagation of fight.
6. We do not see the shadow of the aeroplane flying high in the sky because the Sun is a point source of fight.
7. Fluroscent tube is an extended source of light.
8. If we keep 100 sheets of transparent paper one above the other, the heap of paper would behave as an opaque body.
9. If we keep 100 sheets of translucent paper one above the other, the heap would behave as an opaque body.
10. Regular reflection obeys only one law, namely, the angle of incidence is equal to the angle of reflection.
11. Light does not interact with the living matter.
12. Image formed in a convex mirror is shorter anti real. (xii) Concave mirror always forms a real image.

Answer:

1. False
2. True
3. True
4. False
5. True
6. False
7. True
8. True
9. True
10. False
11. False
12. True
13. False.

Light, Shadows and Reflections Very Short Answer Type Questions.

Question 1.
Name any four man – made sources of light?
Answer:
The man – made sources of light are:

1. An electric bulb
2. A torch
3. A candle
4. A lamp.

Question 2.
Why do objects in a room become visible even if sunlight does not enter it?
Answer:
The objects in a room become visible during the day because of reflection of sunlight by the several non – luminous objects around us.

Question 3.
Give the names of four different sources of light.
Answer:
The four different sources of light are:

1. Sun
2. Stars
3. Moon
4. Firefly.

Question 4.
How does light travel from one point to the other?
Answer:
Light travel from one point to the other in straight line.

Question 5.
Why is the image formed in a pinhole camera inverted?
Answer:
The image formed in a pinhole camera is inverted because light travels in straight lines.

Question 6.
What is luminous objects?
Answer:
Objects like the sum that give out or emit light of their own are called luminous objects.

Question 7.
Does the flame of a gas stove emit light?
Answer:
Yes.

Question 8.
Give one example of living thing, which emits light?
Answer:
Firefly (Jugnu) is a living source of light.

Question 9.
Why translucent objects cast feeble shadow?
Answer:
Translucent objects cast feeble shadows because they allow the partial light to pass through them. So, every light or feeble shadow is formed behind the object.

Question 10.
State the conditions when annular solar eclipse occurs?
Answer:
An annular solar eclipse occurs when only the tip of the umbra of the moon falls on the earth.

Question 11.
Tube light is a cold source of light. Is this statement correct? If yes, then why?
Answer:
Yes, this statement is correct because tube light gives light only. It does not produce any heat. This is why tube light is called a cold source of light.

Question 12.
Classify the following into transparent, opaque and translucent objects: Wax, spectacles, a heap of salt, a stone, dense smoke, wood, skin, balloon, rubber, membrane of a table, blood and milk?
Answer:
Transparent objects:
Spectacles, membrane of a tabla.

Opaque objects:
Wax, wood, a heap of salt, a stone.

Translucent objects:
Dense smoke, skin, balloon, rubber, blood and milk.

Question 13.
What is the meaning of shadow?
Answer:
When any obstacte comes in the way of light then the portion on the screen where light does not reach is called shadow.

Question 14.
Why is the shadow of edges of a blade not clear?
Answer:
Because at the edges of the blade, the light is diffracted, i.e., bent slightly in the shadow region. Hence the edges of shadow of blade are not sharp.

Question 15.
Is the medium required for the propagation of light?
Answer:
No, the light can travel in vacuum.

Light, Shadows and Reflections Short Answer Type Questions

Question 1.
What is light?
Answer:
Light is the external physical reason which makes things visible. Light makes it possible to see the objects but light itself cannot be seen. When light falls on any body, it gets reflected and reaches our eyes and we feed the presence of that body. Light is also a form of energy. It can be converted to other form of energy. Light is propagated in the form of electromagnetic waves. Its wavelength is about 4000 A⁰ to 8000 A⁰. It can travel through vacuum with velocity of 3 x 10⁸ m/see.

Question 2.
What do you mean by luminious and non – luminious bodies?
Answer:
The bodies which themselves are a source of light, and emit light they are called luminious. For examples, the sun, a burning candle, a light bulb, etc. Those bodies which do not emit light but are made visible by light falling from some luminious object on them are called non – luminious bodies. For examples, the earth, the moon, the table, etc.

Question 3.
Give the definitions of

1. Transparent bodies
2. Translucent bodies
3. Opaque bodies.

Answer:

1. Transparent bodies are those through which light can pass freely and through which things can be distinctly seen. For example, air, water, glass, etc.

2. Translucent bodies are those which allow only a part of the light to pass through them and things cannot be seen distinctly. For example, butter-paper, ground glass, etc.

3. Opaque bodies are those which do not allow any light to pass through them and so we cannot through them. For example, stone, iron, wood, etc.

Question 4.
Give the differences between transparent and opaque objects.
Answer:
The differences between the transparent and opaque objects are:
Transparent Object:

• The light passes through these objects.
• They cast no shodow.

Opaque Object:

• The light cannot pass through these objects.
• They cast dark shadows.

Question 5.
State the differences between transluscent and opaque objects.
Answer:
Difference between transparent and transluscent materials:
Transparent Materials:

• The light pass through easily.
• Through it objects can. be seen clearly.

Transluscent Materials:

• It allows a part of light to pass through it.
• Through it objects can only be seen dimly.

Question 6.
How can you see a solar eclipse?
Answer: Solar eclipse can be seen by using a glass. There is another alternative method to see the sun. Take a piece of cardboard having a hole in the centre. This cardboard forms an image of sun on the wall. Thus the solar eclipse can be seen by this image safely.

Question 7.
Mention some of the uses of plane mirror.
Answer:
Uses of plane mirror are:

1. In hair cutting saloons, shops and at home.
2. For constructing periscope.
3. For constructing kelidoscope.

Question 8.
State two properties each of umbra and penumbra.
Answer:
Properties of Umbra:

1. The darkest part of the shadow is called umbra.
2. The light in umbra does not reach from any source of light.

Properties of Penumbra:

1. In this region light reaches from one part of the source.
2. This region is not completely dark.

Question 9.
What is regular reflection?
Answer:
When the light falls on the smooth surface the scattered light rays move in a definite direction. This gives the clear image of the object. This. is called regular reflection.

Question 10.
State the difference between umbra and penumbra.
Answer:
Difference between umbra and penumbra:
Umbra:
The region of the space where the light does not reach from any source, is the darkest. This darkest part of the shadow is called umbra.

Penumbra:
The dark circular path is surrounded by a less dark portion. This shadow part is called penumbra.

Light, Shadows and Reflections Long Answer Type Question

Question 1.
Draw a diagram to show the position of the screen so that no umbra is formed on it if the source of light is bigger than the obstacle.
Answer:

Question 2.
Describe clearly the event of partial lunar eclipse and explain is cause.
Answer:
The ray diagram shows the various positions of the Moon as it passes through the penumbra and the umbra of the earth during a lunar eclipse. At position A, the moon is yet to enter the penumbra and it looks bright as usual. At position B, it has entered the penumbra. At this position, the moon looks pale, as if it has gone behind the clouds. After some time, a part of the moon enters the umbra. This part is then not visible from the earth, but the remaining part of the moon is still visible. This is called a partial lunar eclipse. Lunar eclipse, always takes place on full moon day but not on all full moon days.

Question 3.
How can you make a pin hole camera? Describe.
Answer:
Take two boxes so that one can slide into another with no gap in between them. Cut open one side of each box. On the opposite face of the larger box, make a small hole in the middle [Fig. (a)]. In the smaller box, cut out from the middle a square with a side of about 5 cm to 6 cm. Cover this open square in the box with tracing paper (translucent screen) [Fig. (b)]. Slide the smaller box inside the larger one with the hole, in such a way that the side with the tracing paper is inside [Fig. (c)]. Your pin hole camera is ready for use.

Holding the pin hole camera look through the open face of the smaller box.# You should use a piece of black cloth to cover your head and the pinhole camera. Now, try to look at some distant objects like a tree or a building through the pinhole camera. Make sure that the objects you wish to look at through your pinhole camera are in bright sun. shine. Move the smaller box forward or backward till you get a picture on the tracing paper pasted at the other end.

Question 4.
Describe the working of a its uses?
Answer:
A principle is an obtical instrument which is used to see the overhead objects. In a principls there are two mirror. A and B fixed at the two ends of a vertical tube whose reflecting surfaces are parallel and face each other.

Principle:
It is based on the principle of reflection of plane mirrors which are placed parallel. Light rays are coming through an object and entering from the apperture C. These rays strike on the mirror A at an angle of incidence 45° and is reflected along the axis of the tube striking the mirror at 45° again. This is then finally reflected parallel to their original path and reach is to the eyes of observer.

MP Board Class 6th Science Solutions

MP Board Class 6th Science Solutions Chapter 12 Electricity and Circuits

Electricity and Circuits Textbook Exercises

Question 1.
Fill in the blanks:

1. A device that is used to break an electric circuit is called ……………… terminals.
2. An electric cell has ……………… terminals.

Answer:

1. Switch
2. Two.

Question 2.
Mark ‘True’ or ‘False’ for following statements:

1. Electric current can flow through metals.
2. Instead of metal wires, a jute string can be used to make a circuit.
3. Electric current can pass through a sheet of thermo Col.

Answer:

1. True
2. False
3. False.

Question 3.
Explain why the bulb would not glow in the arrangement show in Fig?

Answer:
The bulb will not glow because the circuit is not completed due to the presence of an insulator between the circuit. Here insulator is screw driver.

Question 4.
Complete the drawing shown in figure to indicate where the free ends of the two wires should be joined to make the bulb glow.

Answer:
The complete diagram in shown below:

Question 5.
What is the purpose of using an electric switch? Name some electrical gadgets that have switches built into them.
Answer:
An electric switch is used to open or close the circuit. Electric gadgets that have switches built into them are freezer, washing machines, microwaves, toaster, heaters, electric – bulb, tube – light, electric iron, etc.

Question 6.
Would the bulb glow after completing the circuit shown in Figure of Question 4 above if instead of safety pin we use an eraser?
Answer:
No.

Question 7.
Would the bulb glow in the circuit shown in Fig.

Answer:
No, because both of the terminal of battery is connecting with one terminal of bulb.

Question 8.
Using the “conduction tester” on an object it was found that the bulb begins to glow. Is that object a conductor or an insulator? Explain.
Answer:
That object is a conductor because electricity can pass through a conductor and not through an insulator. If the object is an insulator then bulb could not glow.

Question 9.
Why should an electrician use rubber gloves while repairing an electric switch at your home? Explain.
Answer:
An electrician use rubber gloves while repairing an electric switch because rubber is a bad conductor of electricity or in other words rubber is an insulator.

Question 10.
The handles of the tools like screwdrivers and pliers used by electricians for repair work usually have plastic or rubber covers on them. Can you explain why?
Answer:
Because plastic and rubber, both are the bad conductor of electricity. Hence, they protect electricians against electric shock.

Projects and Activities

Activity 1.
Make a table to show different materials allows current to pass through it or not.
Answer:
Conductors and Insulators:

Activity 2.
Describe a simple experiment to test whether a given material is a conductor or an insulator.
Answer:
To identify given material is a conductor or an insulator.

Requirements:
Pencil, matchstick, alpin, rubber tube, cell wire, bulb.

Procedure:
Take a small bulb, a battery and a length of wire and connect them in a circuit as show in figure. This circuit is not closed and no current will pass through it. Close the gap between the points A and B by inserting the graphite of your pencil between them. Repeat this by successively replacing the graphite by rubber tube, alpin and matchstick. Record the observations in the table given below.
Table

Electricity and Circuits Additional Important Questions

Electricity and Circuits Objective Type Questions

Question 1.
Choose the correct answer:

Question (i)
S.I. unit of electic current is –
(a) Farad
(b) Volt
(c) Ampere
(d) Coulomb.
Answer:
(c) Ampere

Question (ii)
The types of charges are –
(a) Two
(b) Three
(c) Four
(d) None of these.
Answer:
(a) Two

Question (iii)
Voltaic cell was invented by –
(a) Alessandro Volta
(b) J. F. Volta
(c) Georges Leclanche
(d) None of these.
Answer:
(a) Alessandro Volta

Question (iv)
The principle of a voltaic cell was used by –
(a) J. F. Daniel
(b) Alessandro Volta
(c) Georges Leclanche
(d) None of these.
Answer:
(a) J. F. Daniel

Question (v)
The primary cells are –
(a) Voltaic cell
(b) Daniel cell
(c) Dry cell
(d) All of these.
Answer:
(d) All of these.

Question (vi)
Electric current is the flow of particles with –
(a) A negative charge
(b) A positive charge
(c) Both positive and negative charges flowing opposite to each other.
(d) Either positive or negative charge depending on the material.
Answer:
(a) A negative charge

Question (vii)
The conductors of electricity are –
(a) mica
(6) wood
(c) glass
(d) none of these.
Answer:
(d) none of these.

Question 2.
Fill in the blanks:

1. Flow of ………….. through a conductor, when a potential difference is applied across its terminals, is called electric current.
2. The actual direction of current flowing through a circuit is from negative to positive electrode, whereas the …………….. direction is from negative to positive.
3. S.I. unit of electric current is ……………..
4. …………….. is used to measure current flowing through a conductor and voltmeter is used to measure ……………. difference across the ends of a conductor.
5. The bulb with broken filament is called a …………… bulb.
6. The thin tiny wire inside the glass cover in a bulb is called ……………….
7. The bulb does not glow when the ……………. is open.

Answer:

1. Free electrons
2. Conventional
3. Ampere,
4. Ammeter, potential difference
5. Fused
6. Filament
7. Switch.

Question 3.
Which of the following statements are true (T) or false (F):

1. Materials which do not allow an electric current to flow through them are called conductors.
2. In an electric press which effect of electric current used is heating effect.
3. Rate of flow of charge is called electric current.
4. Electric cell converts chemical energy to mechanical energy.
5. Voltaic cell was invented by Volta.
6. Dry cell is portable.
7. An electric cell cannot to be used in a wrist watch.

Answer:

1. False
2. True
3. True
4. False
5. True,
6. True
7. False.

Electricity and Circuits Very Short Answer Type Questions

Question 1.
What are the essential components of an electric circuit?
Answer:
The essential components of an electric circuit are battery or cell, conductor and a key.

Question 2.
What is an electric circuit?
Answer:
The path of an electric current is referred to as electric circuit.

Question 3.
Can we see electricity?
Answer:
No, we cannot see electricity but can observe its effects.

Question 4.
Name two sources of electric current?
Answer:
The two sources of electric current are Voltaic cell and Daniel cell.

Question 5.
What is a conductor? Give two examples.
Answer:
Substances, such as metals, that can conduct electric current are called conductors. For examples, Copper, Aluminium.

Question 6.
What is an insulator? Give three examples.
Answer:
The materials that do not allow current to pass through them are called insulators. For examples, Mica, Wood and Rubber.

Question 7.
Make a list of materials around you which conduct electricity and a list of those that do not.
Answer:
Conductors of electricity are:
All metals, acid base and salt solutions, aluminium, iron, copper and nickel.

Do not conduct electricity are:
Paper, rubber, wool, nylon, polythene and backelite.

Question 8.
Who supplies electricity to tourch bulb?
Answer:
Electric cell supplies electricity to torch bulb.

Question 9.
What are the ready sources of electric current?
Answer:
The ready sources of electric current are dry cell and battery. Every dry cell and battery had got two terminals or connection points marked (+) and (-).

Question 10.
Which scientist made earliest attempts to obtain an electric current?
Answer:
The earliest attempts to obtain electric current was made in the year 1790 by Alessandro Volta an Italian scientist.

Question 11.
What is a fused bulb?
Answer:
When the filament is broken in a bulb, it is called the fused bulb.

Question 12.
Define an open circuit?
Answer:
When there is a gap between two terminals, it is called an open circuit.

Question 13.
Define a closed circuit?
Answer:
A circuit where there is no gap between two terminals is called a closed circuit.

Question 14.
Draw symbol of (i) a cell, (ii) battery and (iii) a key.
Answer:

Question 15.
Name two insulators?
Answer:
Plastics and rubber.

Question 16.
Who discovered the dry cell?
Answer:
Georges Leclanche discovered the dry cell.

Question 17.
What is meant by battery?
Answer:
The positive terminal of one cell is kept in contact with the negative terminal of the other cell. When two or more then two cells are joined together in this way, we get a battery.

Question 18.
What energy is converted to electrical energy in an electric cell?
Answer:
The chemicals in a cell produce chemical energy. This chemical energy is converted to electrical energy in a cell.

Question 19.
What are the uses of storage batteries?
Answer:
Storage batteries are used where electric current is needed for longer time of more voltage. For examples, in cars, trucks, buses. It is also used in submarines, radars and satellites.

Question 20.
Give some uses of dry cells?
Answer:
Uses of dry cells. In radio, transistor, tourches, remote, camera and calculator.

Question 21.
What is filament of a bulb?
Answer:
The thin wire that gives off light is called the filament of the bulb.

Electricity and Circuits Short Answer Type Questions

Question 1.
What is current?
Answer:
The rate of flow of electric charge through a conductor per unit time is called electric current. In other words, we can say that the amount of electric current is the ratio of charge flowing through a conductor to the time taken in the flowing of the charge.

Question 2.
List the appliances around you that depend on electricity for their operation. List the appliances that do not use electrical energy?
Answer:
Appliances that depend on electricity are:
Electric press, geyser, washing machine, television, radio, fan, cooler etc.

Appliances that do not depend on electricity are:
Cooking gas, stove, solar cooker, sewing machine, cycle, rickshaw, etc.

Question 3.
We selectively choose certain materials to make a path and reject others. Why?
Answer:
Some materials do not allow an electric current to pass through them. Such materials are called insulators. Materials which allow electric current to pass through them are called conductors.

Question 4.
What happens when a charged electroscope is connected to a uncharged electroscope by a wire? What is that called?
Answer:
When a charged electroscope is joined to an uncharged electroscope by a wire, charges flow from the charged to the uncharged electroscope through the wire till they are equalised. This flow of charges forms an electric current. It is measured in ampere.

Question 5.
What is the nature of electric current?
Answer:
As water flows from higher level to lower level in a pipe, electric current also flows from the source of electric current to the target where it is needed through metal wires.

Question 6.
Define an electric switch?
Answer:
A switch is a simple device that either breaks the circuit or completes it. When the switch is open, the circuit is not complete and the current does not flow. In the other position, when the switch is closed, the circuit is complete and current can flow through the circuit.

Question 7.
On what principle scientist Volta made his cell?
Answer:
The principle was that when two strips of different metals are dipped in an acid solution an electric current begins to flow through them. Such a simple source of current, or a cell is called as a voltaic cell in honour of its inventor.

Question 8.
What are the draw backs in voltaic cell? Who then improved the design?
Answer:
Voltaic cell is not a good source of current as the flow through the wire in such a cell is not smooth and steady. J. F. Daniel (1790 – 1845) made an improved design of voltaic cell in the year 1836.

Electricity and Circuits Long Answer Type Questions

Question 1.
Explain an electric cell with suitable diagram and their construction.
Answer:
Electricity to the bulb in a torch is provided by the electric cells. Electric cells are also used in alarm clocks, wristwatches, transistor, radios, cameras and many other devices. In an electric cell their is a small metal cap on one side and a metal disc on the other side. The metal cap is the positive terminal of the electric cell while the metal disc is the negative terminal.

All electric cells have two terminals one positive and another negative terminal. An electric cell produces electricity from the chemical stored inside it. When the chemicals in the electric cell are used up, the electric cell stops producing electricity. The electric cell then has to be replaced with a new one.

Question 2.
What is meant by an electric circuit?
Answer:
When we connect the two ends of a cell to a bulb using copper wires, the bulb lights up. This is because we have provided a path for electrons to flow the negative terminal of the battery to the positive terminal through a bulb. Such a path of an electric current is known as a electric circuit.

Question 3.
Find the various ways in which two batteries and two bulbs can be connected in a working circuit.
Answer:
Two batteries and two bulbs can be connected in working circuit in two ways.
1. In series as shown in figure.

2. In parallel as shown in figure.

Question 4.
Draw a diagram of a torch bulb?
Answer:

Question 5.
Draw a neat diagram to show the inside view of a torch?
Answer:

MP Board Class 6th Science Solutions

MP Board Class 6th Science Solutions Chapter 10 Motion and Measurement of Distances

Motion and Measurement of Distances Text Book Questions

Question 1.
Give two examples each, of modes of transport used on land, water and air.
Answer:

• Land: Railways, buses.
• Water: Ships, boats.
• Air: Aeroplanes, helicopters.

Question 2.
Fill in the blanks:

1. One meter is ……………… cm.
2. Five kilometer is ……………. m.
3. Motion of a child on a swing is ………………
4. Motion of the needle of a sewing machine is ………………
5. Motion of wheel of a bicycle is ……………….

Answer:

1. 100
2. 5000
3. Periodic motion
4. Oscillatory motion
5. Circular motion.

Question 3.
Why can a pace or a footstep not be used as a standard unit of length?
Answer:
A pace or a footstep cannot be used as a standard unit of length because they are different for different people. Moreover, there will be a large difference in a pace and a footstep of child, young and an adult.

Question 4.
Arrange the following lengths in their increasing magnitude:
1 meter, 1 centimeter, 1 kilometer, 1 millimeter.
Answer:
The given lengths in their increasing order are written as:
1 millimeter > 1 centimeter > 1 meter > 1 kilometer.

Question 5.
The length of a person is 1.65 m. Express it into cm and mm.
Answer:
We know that,
1 m = 100 cm
and 1 m = 1000 mm
∴ 1.65 m = 1.65 × 100 cm = 165 cm
and 1.65 m = 1.65 × 1000 mm = 1650 mm.

Question 6.
The distance between Radha’s home and her school is 3250 m. Express this distance into km.
Answer:
We know that,
1 m = \(\frac { 1 }{ 1000 }\) Km
∴ Distance between Radha’s home and her school = 3250m
= 3250 × \(\frac { 1 }{ 1000 }\) km.
= 3.250 km.

Question 7.
While measuring the length of a knitting needle, the reading of the scale at one end is 3.0 cm and at the other end is 33.1 cm. What is the length of the needle?
Answer:
The length of needle = 33.1 – 3.0 cm
= 30.1 cm.

Question 8.
Write the similarities and differences between the motion of a bicycle and a ceiling fan that has been switched on.
Answer:

Similarity:
The motion of a bicycle and ceiling fan are in circular motion.

Dissimilarity:
The ceiling fan moves without changing its position while the bicycle moves with changing its position with time.

Question 9.
Why could you not use an elastic measuring tape to measure distance? What would be some of the problems you would meet in telling someone about a distance you measured with an elastic tape?
Answer:
We should not use an elastic measuring tape to measure distance because the length of an elastic measuring tape will increase when we pull or stretch the tape for measuring the length. The measured length may be increase or decrease due to its elasticity. Thus, we cannot measure the correct length by an elastic measuring tape. The length of any object measured by this elastic tape either will be more or less depending upon the elasticity of the tape.

Question 10.
Give two examples of periodic motion.
Answer:
Examples of periodic motion are motion of a pendulum, a branch of a tree moving to and fro, motion of a child on a swing, strings of a guitar, etc. (any two).

Projects And Activities

Activity 1.
Work in groups and each of you do this activity one by one. Using your foot as a unit of length, measure the length and breadth of the classroom. It is possible that while measuring these you may find some part remains to be measured as it is smaller than your foot.
Answer:
Measuring length and breadth of classroom

Activity 2.
Work in groups and each of you use your handspan as a unit to measure the width of a table or a desk in the classroom.
Answer:
Measuring width of a table

Activity 3.
Think of some objects you have seen recently. List them in Table. A school bag, a mosquito, a table, people sitting on desks, people moving about? May be a butterfly, dog, cow, your hand, a small baby, a fish in water, a house, a factory, a stone, a horse, a ball, a bat, a moving train, a sewing machine, a wall clock, hands of a clock? Make your list as large as you can. Which of these are moving? Which are at rest?
Answer:
Table: Objects in rest and motion

Motion and Measurement of Distances Additional Important Questions

Motion and Measurement of Distances Objective Type Questions

Question 1.
Choose the correct answers:

Question (i)
The SI unit of the length is –
(a) Centimeter
(b) Meter
(c) Decimeter
(d) Kilometer
Answer:
(a) Centimeter

Question (ii)
The SI unit of mass is –
(a) Milligram
(b) Gram
(c) Kilogram
(d) Quintal
Answer:
(c) Kilogram

Question (iii)
SI unit of time is –
(a) Day
(b) Hour
(c) Minute
(d) Second
Answer:
(d) Second

Question (iv)
To read the scale the eye should be vertically –
(a) Upward
(b) Downward
(c) Both
(d) None
Answer:
(a) Upward

Question (v)
Flying kite is an example of –
(a) Circular motion
(b) Periodic motion
(c) Irregular motion
(d) Linear motion
Answer:
(c) Irregular motion

Question 2.
Fill in the blanks:

1. One decameter equals ……………. meters.
2. One decimeter equals ……………. centimeters.
3. One quintal equals ……………. kilograms.
4. One millennium equals ……………. centuries.
5. One metric ton equals …………… quintals.
6. Meter is indicated by sign …………….
7. Kilogram is indicated by sign …………….
8. Second is indicated by sign …………….
9. Changing of day and night is ……………. change.

Answer:

1. 0.1
2. 10
3. 100
4. 10
5. 10
6. m
7. kg
8. s
9. Periodic

Question 3.
State whether the following statements are true (T) or false (F):

1. In ancient India, small length measurements used were an angul (finger) or a mutthi (fist).
2. In 1790, the French created a standard unit of measurement called the metric system.
3. For measuring large distances, meter is not a convenient unit.
4. Handspan is a standard unit of length.
5. Length of a curved line cannot be measured by a meter scale directly.
6. Motion of the balance wheel of a watch is a periodic motion.
7. The motion of a ball rolling on ground is random motion.
8. The motion of a point marked on the black of an electric fan is the example of circular motion.
9. The motion of the moon round the earth is periodic.
10. When a drum is struck gently, its membrane shows random motion.

Answer:

1. True
2. True
3. True
4. False
5. True
6. True
7. True
8. True
9. False
10. False.

Question 4.
Match the items in Column A with Column B:

Answer:

(i) (d)
(ii) (a)
(iii) (e)
(iv) (b)
(v) (c).

Question 5.
Match the items in Column A with Column B:

Answer:

(i) (d)
(ii) (c)
(iii) (a)
(iv) (b).

Motion and Measurement of Distances Very Short Answer Type Questions

Question 1.
How may kilogram are there in one metric ton?
Answer:
1 metric ton = 1000 kg = 10³ kg.

Question 2.
How many seconds are there in one day?
Answer:
Number of seconds in one day=24 × 60 x 60 = 86400 s.

Question 3.
Why a pace or a foot step cannot be used as a standard unit of length.
Answer:
The pace or a foot step vary from person to person. These methods are not satisfactory.

Question 4.
Arrange the following lengths in their increasing order: metre, centimeter, kilometer, millimeter.
Answer:
Millimeter < centimeter < metre < kilometer.

Question 5.
Arrange the following masses in their increasing order: kilogram, quintal, milligram, gram.
Answer:
Milligram < gram < kilogram < quintal.

Question 6.
How many liters would be there in 1000 ml?
Answer:
1 litre, because liter = 1000 ml.

Question 7.
How many seconds are there in 8 minutes?
Answer:
∵ 1 minutes = 60 seconds
∴ 8 minutes = 8 × 60 seconds
= 480 seconds.

Question 8.
How many centimeters means 8 meters?
Answer:
∵ 1 metre = 100 centimeter
∴ 8 meters = 8 × 100 centimeters
= 800 centimeters.

Question 9.
How many meters means 3000 mm?
Answer:
∵ 1 mm = 100 metre
3000
∴ 3000 mm = metre = 3 metre.

Question 10.
To measure the length of chest, what instrument would you use? Can you measure chest with the help of any other method?
Answer:
For measuring the size of chest we use a measuring tape. A metre scale cannot be used. It will not give correct measurement because it is not flexible.

Question 11.
Why hand is not a standard unit to measure length?
Answer:
A hand cannot be used as standard unit of length because the length of hand of all the people are different. So the length measured by one person will differ from the length measured by the other person.

Question 12.
What happens if the tailor takes your measurement with hand?
Answer:
There is variation in the measurement takes by hand because the length of hand-span of every tailor was different.

Question 13.
State any two points necessary for measurement.
Answer:
The measurement is the comparison of any two unknown quantity with same kind of definite known quantity. The measure should be such that it must have same meaning for each individual. To bring uniformity in measurement we use standard units.

Question 14.
At which place, the standard units have been preserved?
Answer:
International standard units have been preserved at the Weight and Measures Bureau in Paris.

Question 15.
Where does the copies of standard units have been preserved in India?
Answer:
In India, one copy of International standard units is preserved at National Physical Laboratory, Pusa Road, New Delhi.

Question 16.
Name the quantity which a shopkeeper measures while selling rice.
Answer:
Kilogram.

Question 17.
Name the two parts which must be mentioned to state the results of a measurement.
Answer:
The two parts are

1. Quantity
2. Unit.

Question 18.
Name the SI units of length?
Answer:
SI unit of length is 1 metre or 9 m.

Question 19.
Name the SI unit of mass?
Answer:
SI unit of mass is kilogram or 9 kg.

Question 20.
What is motion?
Answer:
Motion is the continuous change in position of a body with respect to time as compared to a stationary object. For examples, moving car, moving fan, etc.

Question 21.
Is your classroom at rest or in motion?
Answer:
It is at rest because’ it is not changing its position.

Question 22.
Is the hour’s hand of a wall clock at rest or in motion?
Answer:
The hour’s hand of a wall clock is moving though it moves very slowly.

Question 23.
What type of motion do the vehicles on a straight road perform?
Answer:
The vehicles perform rectilinear motion on the road.

Question 24.
What type of motion does the wheel of a bicycle perform?
Answer:
The wheel of a bicycle perform rotatory or circular motion.

Question 25.
An object is hung from a spring is pulled down and left. What type of motion does the object perform?
Answer:
The object perform oscillatory motion which is also a periodic motion.

Question 26.
Give two examples of periodic motion.
Answer:

1. Rotation of earth on its axis.
2. Moon moves around the earth.

Question 27.
Give two examples of non – uniform motion.
Answer:

1. Motion of the train when its driver applies breaks.
2. Motion of the cricket ball when the bowler throws the ball and the ball is hit by the player.

Question 28.
Name the three types of motion.
Answer:
Three types of motion are rectilinear motion, rotatory motion and oscillatory motion.

Question 29.
Which type of motion does the feet of a tailor perform while sewing some clothes on a sewing machine?
Answer:
The feet of the tailor perform periodic motion while sewing clothes on a sewing machine.

Motion and Measurement of Distances Short Answer Type Questions

Question 1.
What do you mean by measurement, explain with example?
Answer:
The comparision of an unknown quantity with a known standard quantity (called unit) is known as measurement. For example, while buying things, we ask a certain amount of quantity to the shopkeeper, he then weight the exact quantity and gives it to us, like one kg sugar, 5 metre cloth, 10 kg. flour etc.

Question 2.
In our daily life, where we need measurement. Give any five examples.
Answer:
Examples of measurements:

1. To measure the length of cloth before serving.
2. To measure the weight of vegetables before buying.
3. To build house.
4. To reach school in time.
5. To buying milk.

Question 3.
What are the difficulties in using non – standard units?
Answer:
People use foot, arm, stretched palm, etc. as units of length. These non – standard units (or methods) were not satisfactory because lengths of arm, foot and stretched palm vary from person to person. However if there are different units of length in the different parts of the world, it is very inconvenient for the exchange of scientific information. Thus the need for the standard unit been felt. The unit which people agree to use as a basic unit for measurement becomes a standard unit for the group of people for the sake of uniformity.

Question 4.
What do you understand by International System of measurements? Write a short note on it.
Answer:
For bringing the uniformity in units, scientists have done lot of efforts on International level and prepared an unanimous standard system. It is known as International Standard System. It is abbreviated as SI units.In this system length is measured in metre mass in kilogram and time in second. A metre is a distance equal to one million (10-7) time of the distance between equator and pole. A second is 1/86400 times of a mean solar day. A kilogram is equal to one thousand milligrams.

Question 5.
Why standard units are necessary?
Answer:
A quantity adopted as a standard of measurement of physical quantity, is called a unit. In fact, the unit of measurement should be such that the magnitude measurement must be the same even if it is measured by different persons. The measure should be such that it must have same meaning for each individual. To bring uniformity in measurement standard units are necessary.

Question 6.
How can you find out that a given meter scale is correct or not?
Answer:

1. A correct metre sacle has (←, →) signs on its both ends as shown in figure.
2. A correct metre scale has the stamp of the Weights and Measure Department.
3. A correct metre scale is straight, not bent from the centre.
4. A correct metre sacle gives the correct measurement of length.
   

Question 7.
Give three examples of rectilinear motion. Explain.
Answer:

1. A scooterist driving on a road.
2. Soldiers marching in the battlefield.
3. A ball falling from a height.

In all these examples objects change their position with time along a straight line.

Question 8.
Give two examples of rotatory motion. Explain.
Answer:

1. Motion of blades of a fan.
2. Motion of minute hand of the clock.
3. Motion of the wheel of a car.

In these examples the object or any parts of it move in a circular path. This is called rotatory or circular motion.

Question 9.
What are the differing types of motion?
Answer:
The different types of motions are :

1. Linear motion
2. Circular motion
3. Curvilinear motion
4. Oscillatory motion
5. Random motion
6. Periodic motion

A motion can be the combination of all these types of motions or a few of them.

Question 10.
What are periodic and non-periodic motions? Explain with example.
Answer:
Periodic motion:
The motion of a body which is repeated at regular intervals of time is called periodic motion. In periodic motion, a body covers equal distances in equal intervals of time. For exampls, revolution of earth round the sun, the motion of moon round the earth, the motion of a swing, the motion of a pendulum, etc.

Non – periodic motion:
The motion of a body which is not repeated at regular intervals of time is called non-periodic motion. In non – periodic motion, a body does not cover equal distances in equal intervals of time. For examples an athlete running on a track, a moving car on busy road, etc.

Question 11.
How is circular motion different from curvilinear motion?
Answer:
Circular motion is curvilinear motion but it involves the motion of a body at a fixed distance from a fixed point called axis. The figure explains the difference. As motion of the body ‘A’ is around the axis but in second case ‘B’ it is curvilinear motion.

Question 12.
Give a table to show multiples and sub – multiples of units of length, mass and time.
Answer:
Length
10 mm = 1 centimeter (cm)
10 cm = 1 decimeter (dm)
10 decimeter = 100 cm = 1 metre (m)
10 metre = 1 decameter
100 metre = 1 hectometer
1000 metre = 1 kilometer (km)

Mass
1000 (mg) = 1 gram (g)
1000 gm = 1 kilogram (kg)
100 kg = 1 quintal
10 quintal = 1 metric ton

Time
60 seconds = 1 minute
60 minutes = 1 hours
24 hrs. = 1 day
365 days = 1 year
10 years = 1 decade
10 decades = 1 century

Motion and Measurement of Distances Long Answer Type Questions

Question 1.
What precautions are taken while measuring length?
Answer:
The precautions which should be taken while using a metre scale to measure length are the following:

1. The scale should be placed along the length to be measured

2. The scale should be placed very close to the object to be measured.

3. The broken scale should not be used because if used the 1 always begin with the final mark on scale. Subtract the final reading from initial reading to get length e.g., if the initial reading is 4.2 cm and final reading is 6.8 cm. then the length is 6.8 – 4.2 cm = 2.6 cm.

4. To read to scale correctly the eye should be vertically upward. As shown in fig. OA and OC give wrong reading of length while OB gives the correct reading of length.

Question 2.
Identify the measuring instruments given in the pictures and tell where they are used?

Answer:
1. Inch tape:
It is used for measuring height and tailor also uses this inch tape.

2. Steel tape or measuring tape:
It is used for measurement of glass, building height and carpenter also uses this.

Question 3.
Identify the correct method of keeping scale for measuring the length?

Answer:

1. Is the correct method of keeping scale for measuring the length.

Question 4.
With the help of thread and scale find out the length of Rs. 5 coin.
Answer:
Mark a dot on one end of the circumference of the coin. Now put a knot on one end of the thread. Keep it tight on the mark on the coin. Move the thread around the circumference till the mark on the coin is reached again. Mark this position on the thread with a dark pencil. Measure the length of the thread between the knot and the mark. (Do not stretch the thread with a force). This is the length of circumference of five rupee coin.

Verify this length by keeping the thread in stretched position on the table between two tight nails. Mark a dot with a pencil. Place the rupee coin in vertical position. Now slide the coin along the length of thread till the mark on the coin is reached again as shown in the diagram below. Measure the distance between two marks on the thread. This is the circumference of the coin. The two measurement must be exactly identical.

Question 5.
Use a thread to measure the length of a curved line.
Answer:
Mark the ends of curved line by putting full stop. Tie a knot on the open end of the thread. Place the knot of the thread on end A of the line. Now place the thread along the line keeping it tightly gripped with the help of both the thumbs or fore-fingers as in the diagram.

Now move the thumb a little further keeping the thread in position and then press and release the hold on the thread as you keep on sliding the thread along the curves on the line. When the thread reaches the end B mark this position on the thread. You may tie the second knot at this point. Now measure the length of thread between two knots with the help of the metre scale. This is the length of the curved line.

Question 6.
How many kinds of motions are? On the basis of daily experience explain only two of them.
Answer:
The different types of motions are:

1. Linear motion
2. Curvi linear motion
3. Random motion
4. Circular motion
5. Oscillatory motion
6. Periodic motion
7. Non – periodic motion.

A motion can be the combination of all these types of motions or a few of them.

1. Linear motion:
It is also called as translatory motion. It involves the motion of a body along a straight line. For examples, a bullet fired from a rifle, a ball rolling on ground, a child sliding down a slope as shown in fig.

2. Curvilinear motion:
The motion of a body along a curved path is called curvilinear motion. For examples, a cyclist turning on road, a ball falling from a height, a train moving on a curved rail track, football kicked high in air by a player, etc.

3. Random motion:
The motion of a body in which it changes its position rapidly with time in all the possible directions is called random motion. For examples, the motion of a mosquito, the motion of a hockey ball or of football in the ground, etc.

4. Circular motion:
The motion of a body along a circular path about a fixed axis is called circular motion. For examples, revolution of moon around the earth, revolution of earth around the sun, a rotating spinning top, moving wheel, a moving fan, etc.

5. Oscillatory motion:
A body is said to be in oscillatory motion when it moves to an fro about a fixed point. For examples, the pendulum of a wall, clock (Fig.), a swing, a wire of sitar when plucked, striking of drum, etc. Mostly the hanging objects show oscillatory motion.

6. Periodic motion:
The motion of a body which is repeated at regular intervals of time is called periodic motion. In periodic motion, a body covers equal distances in equal intervals of time. For examples revolution of earth round the sun, the motion of moon round the earth, the motion of a swing, the motion of a pendulum, etc.

7. Non – periodic motion:
The motion of a body which is not repeated at regular intervals of time is called non – periodic motion. In non – periodic motion, a body does not cover equal distances in equal intervals of time. For examples an athelete running on a track, a moving car on the busy road, etc.

Question 7.
Give an experiment to show that motion of plucked string is oscillatory motion?
Answer:
Take a thin string and tie it in between the two nails fixed on table. Now pluck the string and observe the motion of the plucked string. We will see that the string moves to and fro along its mean position. This shows that motion of plucked string is Oscillatory
motion.

Question 8.
Why sand grains kept on a drum move up and down on stiling?
Answer:
The drum membrane shows vibratory motion when struck. This vibratory motion of the membrane makes the sand grains dance up and down as shown in figure. As the membrane vibrates above its mean position, the sand grains fly up and then fall down.

MP Board Class 6th Science Solutions

MP Board Class 6th Science Solutions Chapter 9 The Living Organisms and their Surroundings

The Living Organisms and their Surroundings Text Book Exercises

Question 1.
What is a habitat?
Answer:
The place where a plant or an animal lives is called its habitat.

Question 2.
How are cactus adapted to survive in a desert?
Answer:
Cactus plants lose very little through transpiration. The leaves in desert plants are either absent, very small, or they are present in the shape of spines. This helps in reducing loss of water from the leaves through transpiration. The photosynthesis in these plants is usually carried out by the stems. The stem is also covered with a thick waxy layer, which helps to retain water. Cactus plants have roots that go very deep into the soil for absorbing water.

Question 3.
Fill up the blanks:

1. The presence of specific features, which enable a plantor an animal to live in a particular habitat, is called …………….
2. The habitats of the plants and animals that live on land are called ……………. habitat.
3. The habitats of plants and animals that live in water are called ……………. habitat.
4. Soil, water and air are the ……………. factors of habitat.
5. Changes in our surroundings that make us respond to them, are called …………….

Answer:

1. Adaptations
2. Terrestrial
3. Aquatic
4. Abiotic
5. Stimuli.

Question 4.
Which of the things in the following list are non – living? Plough, Mushroom, Sewing machine, Radio, Boat, Water hyacinth, Earthworm.
Answer:
Non – living things are plough, sewing machine, radio and boat.

Question 5.
Give an example of a non – living thing, which shows any two characteristics of living things?
Answer:
Clouds in the sky. They show two living characteristics. These are grow in size and move from one place to another place.

Question 6.
Which of the non – living things listed below, were once part of a living thing? Butter, Leather, Soil, Wool, Electric bulb, Cooking oil, Salt, Apple, Rubber.
Answer:
Butter, Leather, Wool, Cooking oil, Apple, Rubber.

Question 7.
List the common characteristics of the living things?
Answer:
The common characteristics of the living things are growth, movement, life cycle, nutrition (taking food), respiration, excretion, respond to stimuli, show movement, die and reproduction.

Question 8.
Explain, why speed is important for survival in the grasslands for animals that live there?
Answer:
There are few trees or places for animals to hide in the grassland habitats. The animals like lion or tiger prey other animals such as deer. The deer have very fast running speed to help them to run away from the predator’s speed is important for their survival in grassland habitats.

Projects And Activities

Activity 1.
Prepare a table to show that animals, plants and other objects found in different surroundings.
Answer:
Animals, plants and’other objects found in different surroundings:

Activity 2.
What is phototropism. Explain with a diagram.
Answer:
Phototropism is the growth of the plant shoot to the sources of light. Take a potted plant with erect stem. Keep the plant in dark room in which the source of the light should be on any one side. Observe the plant after a weak. We see that the shoot of the plant has bent towards the source of light as shown in figure.

Activity 3.
What is its name and habitat?
Answer:

Answer:

• “Penguin.”
• Habitat: Polar regions.

The Living Organisms and their Surroundings Additional Important Questions

The Living Organisms and their Surroundings Objective Type Questions

Question 1.
Choose the correct answer:

Question (i)
In which of the following thing, life activities are carried out –
(a) Chain
(b) Stone
(c) Banyan
(d) Plastic
Answer:
(c) Banyan

Question (ii)
prepare their own food –
(a) Plants
(b) Things
(c) Creatures
(d) None of these.
Answer:
(c) Creatures

Question (iii)
…………… gives eggs.
(a) Cat
(b) Cow
(c) Hen
(d) Dog
Answer:

Question (iv)
Which one is not a noctural animal –
(a) Owl
(b) Camel
(c) Cockroach
(d) Bat
Answer:
(b) Camel

Question (v)
Pond is an example of habitat.
(a) Aquatic
(b) Desert
(e) Terrestrial
(d) Oceans.
Answer:
(a) Aquatic

Question 2.
Fill in the blanks:

1. The place where the animals live is called …………….
2. Hydra is fnuni in ……………
3. Cactus is the plant found in ……………
4. …………… is an añimal which gives eggs.
5. …………… is a non – flower plant.
6. A group of similar organisms is called …………….
7. The world of living organisms is divided into and …………….
8.  …………….. are both living and non – living.
9. There are some sea animals like dolphins and whales that do not have ………………
10. Changes in our surrondings that makes us respond to them, are called ………………

Answer:

1. Habitat
2. Pond water
3. Desert
4. Snake
5. Fungi
6. Species
7. Plant, animal
8. Viruses
9. Gills
10. Stimuli.

Question 3.
Which of the following statements are true (T) or false (F):

1. Reproduction is a common feature of living and nonliving.
2. The process of give birth to young ones is called as reproduction.
3. Every living being responds to external stimuli. This property is called as response.
4. The plants and animals that live on land are said to live in terrestrial habitats.
5. Breathing is part of a process called respiration. Animals and plants are abiotic components.
6. Abiotic components are also known as physical factors.
7. Zizyphus is an aquatic plant.
8. Many plants reproduce through seeds.
9. There is wide variety of organisms present in different habitats.

Answer:

1. False
2. True
3. True
4. True
5. True
6. False
7. True
8. False
9. True
10. True.

Question 4.
Match the items of Column A with Column B:

(i) (c)
(ii) (d)
(iii) (a)
(iv) (b)
(v) (f)
(vi) (e)

The Living Organisms and their Surroundings Very Short Answer Type Questions

Question 1.
What is an organisms?
Answer:
All living creatures of various kinds are organisms.

Question 2.
Name some animals which lay eggs?
Answer:
Frog, snakes, birds, etc. lay eggs.

Question 3.
Name animals which give birth to their young ones.
Answer:
Woman, cow, monkey, etc. give birth to their young ones.

Question 4.
What are biotic components?
Answer:
Plants and animals are biotic components.

Question 5.
What are abiotic components?
Answer:
Water, air, light, soil and heat are abiotic components.

Question 6.
How do plants obtain their food?
Answer:
Plants prepare their own food in their green leaves with carbon – di – oxide, water, minerals and sunlight.

Question 7.
How do the plants prepare their food?
Answer:
Plants take carbon – di – oxide from air water and sunlight. They prepare their food with the help of these and leave out oxygen.

Question 8.
Give example of organisms who do not need light and live underground?
Answer:
Earthworm, cockroach, rats and termites, etc. live in. burrows and are active at night.

Question 9.
Some names of living things are given below. Divide them in two groups (i) giving eggs, (ii) giving birth to young ones. Cockroach, Cat, Dog, Bird, Cow, Lizard, Parrot, Crow, Horse?
Answer:

1. Living being which lay eggs are cockroach, bird, lizard, crow and parrot.
2. Living being which give birth to young ones are cat, dog, cow and horse.

Question 10.
What is the food of a frog?
Answer:
Small insects.

Question 11.
What is the food of fishes?
Answer:
lt feeds up micro plants and aquatic insects.

Question 12.
What is the scientific name of human being?
Answer:
Homo – Sapines.

Question 13.
Name any three desert animals?
Answer:
Lizard, camel, snake.

Question 14.
Name any two desert plants?
Answer:
Kikar, cactus.

Question 15.
Name any two aquatic animals?
Answer:
Fish, coral.

Question 16.
Name three non – living things in a pond?
Answer:
Water, mud and air.

Question 17.
Name two living organisms in a pond?
Answer:
Frog and fish.

Question 18.
Name some animals which are found at mountains?
Answer:
Snow – bear, musk deer, wolf and water fowl.

Question 19.
How is light essential for plants?
Answer:
Plants prepare their own food in the presence of light.

Question 20.
Where do you find yak?
Answer:
At mountains.

Question 21.
What kind of trees do you see on Himalayan mountains?
Answer:
Pines, deodars, oaks.

Question 22.
What is adaptation?
Answer:
The presence of specific features or certain habits, which enable a plant or an animal to live in its surroundings is called adaptation.

Question 23.
What is excretion?
Answer:
As a result of various chemical (metabolic) reactions taking place in the body of cells certain harmful toxic substances are constantly formed. Removal of these toxic substances from j the body is termed as excretion.

Question 24.
Define respiration with the help of chemical equation?
Answer:
The process in which the oxidation of absorbed food is takes place by the 0₂ which is inhaled by breathing and energy is released out is called respiration. Chemical equation of nutrition is as follows:
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + 673 kcal (Energy)

Question 25.
Where will you find the birds?
Answer:
We find the birds on the branches of trees.

Question 26.
Name the habitat of monkey and cactus?
Answer:
The habitat of monkey is trees while the habitat of cacutus is desert.

The Living Organisms and their Surroundings Short Answer Type Questions

Question 1.
What are biotic components? Name some abiotic components.
Answer:
Plants and animals are part of biotic components. In addition, there are small organisms like fungi and bacteria in the habitat, which cannot be seen with naked eyes. These are called micro – organisms. They are also a part of biotic components of different habitat. Some abiotic components are rocks, soil, air and water.

Question 2.
Define terrestrial habitats and aquatic habitats.
Answer:
The plants and animals that live on .land are said to live in terrestrial habitats. For example; forests, grasslands, deserts, coastal and mountain regions. On the other hand, the habitats of plants and animals that live in water are called aquatic habitats. For example, lakes, rivers and oceans, etc.

There are large variations in forests, grasslands, deserts, coastal and mountain regions located in different parts of the world. This is true for all aquatic habitats as well.

Question 3.
Define mountain habitats. Also explain tree of a mountain habitat?
Answer:
Mountain habitats are normally very cold and windy. In some areas, snowfall may take place in winters also. There is a large variety of plants in the mountain regions. These trees are normally cone shaped and having sloping branches. The leaves of some of these trees are like needle. This helps the rainwater and snow to slide off easily. There could be trees with shapes very different from these that are also present on mountains: They have different type of adaptations to survive on the mountains.

Question 4.
List some common features of the living and non – living?
Answer:
Common features of living and non – living are:

1. All of them have mass, shape, and they occupy space.
2. They are made up of structural units.
3. The structural units of living and non – living are called molecules respectively.

Question 5.
In what ways living things differ from non – living things?
Answer:
The living things differ from non – living in the following ways:
All the living are characterized by movement, execution respiration intake of food, reproduction and sentivity towards such, heat and sound.

Question 6.
What do you understand by life cycle and life span of the living things?
Answer:
In living things life starts with a single cell which developes to a mature plant or full grown animal and finally grows old. This whole cycle is called the life cycle. Life span is the time period for which animals grow till they die. This time varies from a few minutes to hundreds of years. Life span of bacteria is short and the life of span a banyan tree may be even hundred of years.

Question 7.
‘All living things respond to external stimuli’. Explain.
Answer:
An important character of plants and animals is their response to external stimuli that is touch, fight, sound, water, chemicals or smell. Plants grow in the direction of fight. Earthworm moves away from fight and saline medium. Cockroaches five in dark corners.

Question 8.
How can you say that plants respond to stimulus?
Answer:
Plants like animals respond to stimulus. For example, the shoot grow towards fight and root grow towards water. The touch – me – not plant shows the most clear example as its leaves drops on touching.

Question 9.
How do plants differ from each other?
Answer:
Plants differ from each other in their habitat, food habits, structure, shape of leaves, type of flower, type of fruit, etc. Some plants five in water, others in marshes and still others on land. Some plants are green, others are non – green, some plants have their body divided into stem, root or leaf but in others there is no stem, root or leaf.

Question 10.
What is photosynthesis?
Answer:
Photosynthesis is the process by which the green plants manufacture their own food from carbon dioxide and water in presence of sunlight. In the process they produce oxygen also.

Question 11.
Name five plants and five animals whose habitat is pond.
Answer:
Pond is the habitat for variety of plants and animals.

Plants found in pond:
Spirogyra (algae), water lily, hydrilla, water hyacinth, sundew, bladder wort. Sundew and bladder wort are insectivorous plants.

Animals found in pond:
Frog, fish, trutles, ducks, snail, kingfisher, etc.

Question 12.
How does reproduction take place in plants and creatures?
Answer:
Every adult living being has the capability to give birth to child like itself. For example, adult cat gives birth to its young ones, and they grow and become adult. The reproduction in plants take place when the seeds sowed in the soil get germinated, sprout out and a sapling is born. Gradually it grows up and become a plant. In case of some of the plants, Certain portion is put under the soil.

Question 13.
How is the growth in plants different from growth in animals?
Answer:
The growth in plants is a continuous process. It occurs throughout their life. In animals the growth occurs only for a limited period of time. For example, in human growth takes place only in the first twenty years of life.

Question 14.
Why is the process of excretion important for living?
Answer:
As a result of metabolism various toxic substances are continuously formed. These wastes (carbon dioxide, ammonia compounds, other salts) if allowed to accumulate in the body (cells), would disturb the chemical composition of the protoplasm and produce toxic effects, crippling the life activities. Hence their elimination is most important. This is done by the process of excretion.

The Living Organisms and their Surroundings Long Answer Type Questions

Question 1.
What are the surroundings in sea and desert regions?
Answer:
In the sea, plants and animals are surrounded by saline (salty) water. Most of them use the air dissolved in water.
There is very little water available in the desert. It is very hot in the day time and very cold at night in the desert. The animals and plants of the desert live on the desert soil and breathe air from the surroundings. The sea and the desert are very different surroundings and we find very different kind of plants and animals in these two regions.

For example, a fish and a camel. There are so many kinds of fish. All the ones shown here have the streamlined shape. This shape helps them move inside water. Fish have slippery scales on their bodies. These scales protect the fish and also help in easy movement through water. Fish have flat fins and tails that help them to change directions and keep their body balance in water. Gills present in the fish help them to use oxygen dissolved in water.

The body structure of a camel helps it to survive in desert conditions. Camel have long legs which help to keep their bodies away from the heat of the sand. They excrete small amount of urine, their dung is dry and they do not sweat. Since camels lose very little water from their bodies, they can live for many days without water.

We see that the features of a fish help it to live inside water and the features of a camel help it to survive in a desert.

Question 2.
Define acclimatisation?
Answer:
There are some changes that can happen in an organism over a short period of time to help them adjust to some changes in their surroundings. For instance, if we live in the plains and suddenly go to high mountain regions, we may experience difficulty in breathing and doing physical exercise for some days. We need to breathe faster when we are on high mountains.

After some days, our body adjusts to the changed conditions on the high mountain. Such small changes that take place in the body of a single organism over short periods, to overcome small problems due to changes in the surroundings, are called acclimatisation. These changes are different from the adaptations that take place over thousands of years.

Question 3.
How animals living in mountain regions adapt themselves? Is there any change in surroundings?
Ans. Animals living in the mountain regions are also adopted to the conditions there. They have thick skin or fur to protect them from cold. For example, yaks have long hair to keep them warm. Snow leopard has thick fur on its body including feet and toes. This protects its feet from the cold when it walks on the snow. The mountain goat has strong hooves for running up the rocky slopes of the mountains.


As we go up in the mountainous regions, the surroundings change and we see different kinds of adaptations at different heights.

Question 4.
Discuss the features of lion and deer that help them to survive in forests or grasslands?
Answer:
A lion lives in a forest or a grassland and is a strong animal that can hunt and kill animals like deer. It is light brown in colour. Lions have long claws in their front legs that can be withdrawn inside the toes. It’s light brown colour helps it to hide in dry grasslands when it hunts for prey (animals to eat). The eyes in front of the face allow it to have a correct idea about the location of its prey.

A deer is another animal that lives in forests and grasslands. It has strong teeth for chewing hard plant stems of the forest. A deer needs to know about the presence of predators (animals like lion that make it their prey) in order to run away from them and not become their prey.

It has long ears to hear movements of predators. The eyes on the side of its head allow it to look in all directions for danger. The speed of the deer helps them to run away from the predators. There are many other features of a lion, a deer or other animals and plants that help them to survive in their habitat.

Question 5.
Which life activities take place in livings being? Explain every activities in three to four sentences.
Answer:
The life activities take place in living being are as follows:

1. Nutrition:
Nutrition is very much essential for living beings for growth and for sustaining life. Every living being takes food in some or other form which provides nutrients to its body.

2. Respiration:
The process of respiration takes place in every living being. There can not be a life without respiration. Generally, the respirations is called as breathing. Exhaling and inhaling are the two steps of respiration.

3. Excretion:
To extrete urine and other harmful material out of body is the most important characteristics of living being. The harmful things like urine, stools, sweat and carbon – di -oxide, etc. are excreted through excretory organs of living beings.

4. Reproduction:
Every adult living being has the capability to give birth to child like itself.

5. Growth:
When we sow seed, it germinates, sprout out, gradually grows and it becomes adult. In this way, the growth takes place in every living being and this process is called growth.

6. Movement and Speed:
Movement and speed is one of the important property of living things. Animals move from one place to another in search of food or to save themselves from enemies. Like animals, no movement takes place in case of plants but despite remaining stationary at one place, they do their movements for procurring sunlight.

7. Response:
Every living being is sensational to the external stimulus. For example, during winter we wear woolen clothes.

Question 6.
What do you mean by growth?
Answer:
Growth means an increase in the size, weight or volume of an organism. It is permanent change in a living organism. The growth in animal is limited only upto the primary stages of life. In plants, the growth is unlimited and continues upto the last stage of life.

Question 7.
Discuss the reproduction in animals.
Answer:
Animals reproduce their own kind. The mode of reproduction may be different, in different animals. Some animals produce their young ones through eggs. Some animals give birth to the young ones. [See figure (i)] Many birds lay their eggs in the nest. Some of the eggs may hatch and young birds come out of these. [See figure (ii)]

Question 8.
Discuss the reproduction in plants.
Answer:
Plants also reproduce. Like animals, plants also differ in their mode of reproduction. Many plants reproduce through seeds. Plants produce seeds, which can germinate and grow into new plants. [See figure (i)]

Some plants also reproduce through parts other than seeds. For example, a part of a potato with a bud, grows into a new plant. [See figure (ii)] Plants also reproduce through cuttings.

MP Board Class 6th Science Solutions