Category: Class 6

NCERT Solutions for Class 6 Science Chapter 16 Garbage In Garbage Out

Topics and Sub Topics in Class 6 Science Chapter 16 Garbage In Garbage Out:

Section Name	Topic Name
16	Garbage in, Garbage out
16.1	Dealing with Garbage
16.2	Vermicomposting
16.3	Think and Throw
16.4	Recycling of Paper
16.5	Plastics boon or a curse?
16.6	Summary

 1. (a) Which kind of garbage is not converted into compost by the redworms?
(b) Have you seen any other organism besides redworms, in your pit? If yes, try to find out their names. Draw pictures of these.
Ans:
(a) Garbage substances like broken glass, aluminium wrappers, plastic items, polythene bags, which are non-biodegradable cannot be converted into compost by the redworms.
(b) Yes, saprophytic organisms such as moulds (white, black or greyish cottony patches) and bacteria (which can be seen under microscope) that help in decomposing biodegradable substances.

2. Discuss:
(a) Is garbage disposal the responsibility only of the government?
(b) Is it possible to reduce the problems relating to disposal of garbage?
Ans:
(a) Along with government and local municipality corporations, it is also the duty of every citizen to help in garbage disposal.A clean environment is necessary to keep us healthy and also to avoid spread of diseases.We should throw garbage at proper places, such as dustbins so that Safai Karamcharis cam collect the garbage easily.
(b) It is possible to reduce the problems relating to disposal of garbage, if we adopt the following means:
(i) The garbage should be thrown at proper places. It should not be thrown ‘ on streets, roads, parks, etc.
(ii) The part of the garbage that can be reused should be separated from the one that cannot be used. The non-useful components should be disposed off at landfill areas.
(iii) Follow the rule of Three R’s:
A. Reduce: Use the things in minimum amount which is necessary to fulfil your requirement.
B. Recycle: The things such as plastic, paper, glass and metals separated from the garbage may be recycle to make new things instead of dumping them along with other wastes.
C. Reuse: It means use of things again and again. For example, plastic bottles of jam or pickle can be used for storing things in the kitchen.

3. (a) What do you do with the left over food at home?
(b) If you and your friends are given the choice of eating in a plastic plate or a banana leaf plotter at a party, which one would you prefer and why?
Ans:
(a) Left over food at home along with other kitchen waste like vegetable peel, paper are dumped into compost pit to convert them into manure. Later on manure is used to grow plants.
(b) We will select banana leaf platter because it can be easily converted into manure by composting.
Plastic plate can be recycled but in this process it gives out harmful gases which pollute the environment. Plastic items cannot be converted into manure by composting.

4. (a) Collect pieces of different kinds of paper. Find out which of these can be recycled,
(b) 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?
Ans:
(a) Pieces of papers obtained from newspaper, notebooks, magazines, etc. can be recycled. Plastic coated and shiny papers cannot be recycled easily.
(b) The surface of recycled paper is rough whereas surface of new sheet of paper is smooth.

5. (a) Collect different kinds of packaging material. What was the purpose for which each one mas used? Discuss in groups.
(b) Give an example in which packaging could have been reduced.
(c) Write a story on how packaging increases the amount of garbage.
Ans:
(a) Packaging materials like thermocole, foam sheets, paper cuttings, card board, jute are used to protect the articles.Card boxes, plastic containers and tin containers are used to facilitate transportation of the packed materials.
(b) Packaging of toys, clothes, shoes, chocolates can be reduced.
(c) We use packaging materials to protect the articles and also to make package good- looking. For example, to give a gift on birthday, the gift is packed and wrapped in a shiny paper or plastic-coated paper. After use the packing material is thrown in dustbin. Similarly, plastic bags, cans, aluminium foils, plastic or aluminium cans and other packaging materials are used and thrown out after use.
Many things such as ghee, refined oil, soaps, detergents and most of eatable goods are sold in small packets.
All the above said measures can help in reducing the amount of garbage due to packing.

6. Do you think it is better to use compost instead of chemical fertilisers? Why?
Ans:  Because:

1. Compost is eco-friendly and harmless. It maintains the texture and fertility of the soil.Chemical fertilisers destroy the natural composition of soil and have adverse effect on human health.
2. Composting helps in recycling of matter and also in disposal of garbage. Leaching of chemical fertilisers causes water pollution and death of aquatic organisms.
3. The production of compost is easy, cheap and harmless whereas production of chemical fertilisers is costly and problematic.

Class 6 Science Chapter 16 MULTIPLE CHOICE QUESTIONS

Choose the correct option:
1. Landfill are is a/an:
(a) open area
(b) high lying open area 
(c) open area near a river/lake
(d) low lying open area
2. The rotting of garbage is said to be completed when the garbage:
(a) rot completely and not smell
(b) rot almost completely, but still smell bad
(c) rot only partially
(d) not change at all
3. Which of the set of items not good for making compost?
(a) Plastic paper, tin foil, wrappers
(b) Broken plastic toys, polythene bags, pieces of clothes
(c) Egg shells, vegetable and fruit peels and tea leaves
(d) Aluminium wrappers, plastic bags and dry leaves
4. Which of the following animals are used for making compost?
(a) Redworms
(b) House fly
(c) Cockrach
(d) Mosquitoes
5. Leaves falling from trees should be:
(a) dumped in landfill areas
(b) dried and burnt
(c)  used in making compost
(d) dumped near the ponds and takes
Ans:
1. (d)
2. (a)
3. (c)
4. (a)
5. (c)

Class 6 Science Chapter 16 VERY SHORT ANSWER TYPE QUESTIONS

1. What is a landfill? 
Ans: A low-lying open area is called landfill.

2. What are blue coloured bins used for?
Ans: Blue bins are used for collecting materials that can be recycled.

3. Give example of material that can be used again.
Ans: Plastics, metals and glass.

4. What type of garbage is thrown in green bins?
Ans: Kitchen and other plants or animals wastes.

5. Define composting.
Ans: The rotting and conversion of some materials into manure is called composting.

6. Explain the term vermicomposting.
Ans: The method of preparing compost with the help of redworms is called vermicomposting.

7. What are redworms?
Ans: Redworms are a type of earthworms which help in preparing compost from the kitchen wastes and parts of plants or animals.

Class 6 Science Chapter 16 SHORT ANSWER TYPE QUESTIONS

1. We should not add wastes containing salts, pickles, oil, vinegar, meat and milk products in vermicomposting pit to feed the redworms. Why?
Ans: Addition of substances such as salts, oil, pickles, vinegar, meat and milk products to vermicompost pit causes growth of disease-causing small organisms. They may cause harm to redworms and hinder in preparation of vermicompost.

2. How can the non-useful component be reused?
Ans: The non-useful components of the garbage are separated by Safai Karamcharis. This separated non-useful components of garbage is spread over the landfill and then covered with a layer of soil. Once the landfill is completely full, it is usually converted into pork or a playground. For the next 20 years or so, no building is constructed on it.

3. What do we do to the useful components (biodegradable) of the garbage?
Ans: Generally, useful components of the garbage are used to make compost. Compost are usually developed near the landfill.
(i) For preparing compost, waste materials like fruit and vegetable peel, egg shells, used tea leaves, waste food, dry leaves, newspapers etc. should be dumped in a pit.
(ii) The pit is covered with soil.
(iii) After 20-25 days, observe the garbage. If the garbage is rot, turned black in colour and no foul smell is emitted, it means rotting of garbage is complete and compost is ready to use.

4. What do you mean by composting?
Ans: The garbage containing plant and animal wastes, waste food, when left as such in pits or heaps is acted upon by bacteria, fungus-like organisms causing rotting. Rotting leads to the formation of manure. It is conversion of complex molecules into simple molecules which can be used by plants for growth and development. Thus, rotting and conversion of some organic materials into manure is called composting.

5. Why should we not bum dried plant leaves and husk? What is the best way to get rid of them?
Ans: Burning of dried leaves, husk and other plant parts produces smoke and gases that are harmful to our health.Dried leaves, husk and other plant parts can be used for preparing compost.

6. List waste products produced from an industry.
Ans: The waste products produced from an industry are:

1. Chemicals
2. Smoke
3. Ash
4. Empty containers such as glass bottles, plastic articles, wrappers.
5. Plastic bags
6. Broken things, iron or other metals

7. What will happen if garbage is left open in bin?
Ans: (i) Garbage will rot and bad smell will spread all around the surroundings.
(ii) Garbage will become breeding spot for flies, mosquitoes and other disease- causing small organisms.
(iii) Due to flies, mosquitoes and other organisms many diseases will spread in the community.
(iv) Rotting garbage may cause air pollution and spread of respiratory disease such as breathing problems.

8. Waste may contain the following things:
Ans:

1. Empty bottles
2. Syringe
3. Needles
4. Ampute
5. Used cotton
6. Injection bottles
7. Used bandages
8. Pieces of plaster
9. Tablet wrapper
10. Empty paper boxes
11. Polythene bags
12. Left over food items
13. Peels of fruits and vegetables.

9. What is papier-mache? How does it help us?
Ans:  Papier-mache is a paste made from pulp of waste papers and clay used for moulding into boxes, trays, etc. This helps in recycling of paper.

10. Can you replace the following packaging material with those which can be recycled or reused.
(1) Milk packets of polythene.
(2) Dry eatables in polythene.
(3) Gift items packed with shiny material.
(4) Glass tumblers packed in thermocole box.
Ans: (1) Glass bottles or recycling polythene.
(2) Paper bags coated with thin sheet of aluminium or recycling polythene.
(3) Beautifully designed paper or recycling shiny material.
(4) Glass tumblers packed in straws placed card-board boxes. As thermocole cannot be recycled.

Class 6 Science Chapter 16 LONG ANSWER TYPE QUESTIONS

1. List the biodegradable and non-biodegradable waste products in your school What are the best ways to get rid of this garbage?
Ans: Biodegradable wastes:
(i) Paper container
(ii) Chalk boxes
(iii) Pencil scraps
(iv) Faeces and urine
(v) Loose and tom waste paper of exercise notebooks and diaries
(vi) Dropout leaves and twigs
(vii) Fruit peels and flower wastes
Non-biodegradable wastes:
(i) Broken glass wares
(ii) Plastic and geometrical instruments
(iii) Plastic and polythene containers
(iv) Wrappers of toffee, aluminium foil
(v) Broken iron wire pieces
Disposal of Wastes:
Biodegradable garbage can be put in a pit made in one comer of the school compound. Cover the garbage with soil, spray some quantity of water. When this pit is full of degradable items cover it with a mixture of dung and clay for a few weeks.             .
After a few weeks when an odour stops coming out from the pit. It indicates that all the degradable material has been converted into compost manure.
The non-biodegradable garbage can be sold to Kabari or can be dumped in a landfill.

2. What are the uses of plastic?
Ans: Uses:
(i) Plastic container can be used to store edible goods.
(ii) Goods packed in plastic pack can be taken anywhere easily and are water proof.
(iii) Plastic containers or articles are good-looking, light in weight, cheap and durable.
(iv) Plastic containers such as bottles can be used to store chemicals. No chemical effects on it.
(v) Plastic can be recycled.

3. What are the demerits of plastic?
Ans: Demerits of plastic:
(i) Plastics give out harmful gases upon heating or burning. These gases may cause many health problems, including cancer in humans.
(ii) Some people often fill garbage in plastic bags and throw it away in open. When stray animals look for food in these bags, they swallow plastic bags along with food. Sometimes, they die due to this.
(iii) The plastic bags thrown away carelessly on roads and other places get into drains and the sewer system.
These plastic bags choke the drains. As a result dirty water spills on road. It causes spread of bad smell and diseases.

4. What suggestions you will give to members of locality to solve the problem of waste material?
Ans: I will suggest the member of my locality to use biodegradable waste in preparing compost.
To take people in confidence, you should make efforts to show the path for preparing compost:
(i) You should select a comer of your locality.
(ii) Dig a pit at open place and ask all the residents to throw their kitchen waste in this pit. Cover the biodegradables in the pit with layers of soil.
(iii) Cover the pit with the mixture of soil and dung.
(iv) After 5-6 weeks, open the pit and show it to the resident of your colony. Also explain that their disposed off material has converted into compost manure.
(v) You can convince RWA (Resident Welfare Associations) to use this manure for colony parks and also in plant pots kept in individual houses for , beautification.

5. Why should we be careful in using plastic bags to store cooked food items?
Ans: 
(i) Sometimes the plastic bags may not be suitable for keeping eatables.Consuming food packed in such plastic bags could be harmful to our health.
(ii) Many a time shopkeepers use plastic bags that have been used earlier for other purpose.
(iii) Sometimes bags collected by rag pickers are also used after washing them. Use of such recycled plastic bags to keep food items could be harmful for our health. So, shopkeepers can be stressed upon the use of plastic bags approved by the authorities.

6. List the steps for preparing vermicompost.
Ans: 
(i) Dig a pit about 30 cm deep or select a wooden box.
(ii) Spread a net or chicken mesh at the bottom .of pit or box. You can also spread 1 to 2 cm thick layer of sand.
(iii)Spread some vegetable wastes including peels of fruits over the sand layer. You can use green leaves, husk or pieces of newspaper, dried stalks of plants and dried animal dung.
(iv) Sprinkle some water to make the layer wet. Do not
(a)Use excess of water
(b)Press layer of leaves or waste so that it has sufficient air and moisture,
(v) Now, buy some redworms and put them in the pit.
(vi) Cover them loosely with a gummy bag or an old sheet of cloth or a layer of grass.
(vii) Redworms need food. So you can provide them as food—vegetable and fruit peels, coffee and tea remains and weeds from the field or garden. Bury this food about 2-3 cm inside the pit.
(viii) Do not put salt, pickles, oil, vinegar, meat and milk preparations. This may cause growth of disease-causing organisms. Redworms do not survive in very hot or very cold surroundings.
(ix) After 3-4 weeks, put some waste food in one comer of the pit. Most of the worms will shift towards newly added food.
(x) Remove the compost from the vacated part and dry it in the sun for a few hours. The vermicompost becomes ready for use.

7. Observe the bins and waste material heaps and suggest what materials can be used for preparing handicrafts materials.
Ans: The following handicraft items can be prepared from the waste materials usually seen in bins and waste storage.

1. Designs and sceneries on cardboard, pencil scrab can be used.
2. We can prepare basket, toys, flower vase, etc.
3. Egg trays can be prepared by papier-mache prepared from waste paper decorated with the help of different colours and can be used.
4. Empty earthen cup (kullarh) can be used as Janjhi by making small hole in it and putting a burnt candle. Light comes out in different designs.
5. Flower vase can be prepared with the help of ice-cream sticks.
6. Different types of toys are prepared with the help of plastic cup, spoon, plate, forks.
7. Models of historical monuments can be designed with the help of empty injection bottles and amputes.

You can prepare other objects with the help of your friends, brothers, sisters, relatives, parents and teachers.

8. Explain one wag of recycling of waste paper.
Ans:  One way to recycle the waste papers is as given below:

1. Collect old newspapers, magazines, used notebooks, envelopes and tom out used papers.
2. Make small pieces of paper of these items and put them in a bucket or any other container submerged in water for one or two days.
3. Make thick paste of wet paper by pounding it. Spread the waste paste on the wire mesh fixed to the frame. You can use a large-sized seive in place of a frame.
4. Pat the layer of paste gently to make the layer of the paste as uniform as possible. You may spread an old cloth or a sheet of newspaper on the paste to soak up the extra water.
5. Remove the layer of paste from the frame and spread it on a sheet of newspaper in the sun. Put some weight on the comers of the newspaper so that these do not curl up.
   You can decorate the paper by adding food colours, dried leaves, flower petals or pieces of coloured paper in the paste.
   This will help you to get a recycled paper with beautiful patterns on it.

9.What can we do to reduce overuse of plastics?
Ans: 

1. Re-use of the plastic bags whenever it is possible to do so without any adverse affects. Neglect re-use of plastic bags for storage or storage of food items to store food items.
2. Insist shopkeepers to use paper bags or jute bags to carry goods purchased,
3. Do not use plastic bags, especially to store eatables.
4. Do not throw plastic bags.
5. Don’t fill plastic bags with wastes of plants and animals, such as peels of vegetables and fruits, egg shells, bone pieces of animals, and throw them here and there in open places.
   Animals may eat such plastic bags for the sake of food items. Later on these cause death of animals such as cow. buffaloes, dogs and other stray animals. These plastic bags, sometimes suffocate them or choke the alimentary canal which causes indigestion of food and elimination of undigested food.
6. Do not bum plastic bags and other plastic items because they emit harmful gases.

10. Municipality provides two types of dustbins for garbage collection. One coloured with blue colour and other with green colour. From following wastes which you will put in the which dustbin?
Plastic materials, metals and glass items, wastes of plants and animals, peels of fruits and vegetables, dried leaves and twigs, remains of meat like flesh and hopes.
Ans: 
(i) The material which can be recycled should be put in the blue dustbin. These materials are: plastic materials, waste metals and glass. It means that the materials which can be recycled and reused should be put in the blue dust bin. These materials cannot rot but can be recycled.
(ii) The wastes of plants and animals, peels of fmits and vegetables, dried leaves and plant twigs, kitchen wastes and other wastes of plant and animal wastes, etc. should be dumped in the green bin or bag. This means that biodegradables are collected in the green dustbin which can be used to prepare compost.

11. Can you make something useful of these waste material?Powder containers, cold-drink cans, plastic bottles, shoe-box.
Ans:
(a) Powder container: Their use depends upon their size, shape and the material they are made of. For example
(i)elongated metallic powder container can be used as pen-pencil stand, to grow money-plant etc.
(ii) plastic containers can be recycled.
(b) Drink cans: Storing liquids like oils, growing herbaceous plants like money- plants etc.
(c) Plastic bottles: Storing liquids such as oils and recycling plastic.
(d) Shoe-box: Making small red-cross box, storage pen-pencils and other small articles.

NCERT Solutions

NCERT Solutions for Class 6 Science Chapter 15 Air Around Us

Topics and Sub Topics in Class 6 Science Chapter 15 Air Around Us:

Section Name	Topic Name
15	Air Around us
15.1	Is air present everywhere around us?
15.2	What is air made up of?
15.3	How does oxygen become available to animals and plants living in water and sons?
15.4	How is the oxygen in the atmosphere replaced?
15.5	Summary

1. What is the composition of air?
Ans: Air is mixture of nitrogen, oxygen, carbon dioxide, water vapour and a few other gases. Some dust particles may also be present in it.

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

3. How will you show that air supports burning?
Ans: Take a small burning candle. Cover the burning candle with a glass jar. After few minutes the candle is extinguished. As the supply of air is stopped due to glass jar the burning of candle is also stopped. This experiment proves that air supports burning

4. How will you show that air is dissolved in water?
Ans: Take some water in a glass vessel or beaker. Heat it slowly on a tripod stand. Before the water begins to boil, look carefully at the inner surface of the vessel. You will see tiny bubbles on the inside. On heating, air dissolved in water escapes in the form of these bubbles.

5. Why does a lump of cotton wool shrink in water?
Ans: Lump of cotton wool has air among gaps of cotton fibres. When water replaces the air from these gaps, the cotton lump becomes heavy and also shrinks due to removal of air gaps.

6. The layer of air around the earth is known as………………….
Ans: Atmosphere

7. The component of air used by green plants to make their food, is………………….
Ans: Carbon dioxide.

8. List five activities that are possible due to presence of air.
Ans: The activities that are possible due to the presence of air, are:
(a) To make a simple firki
(b) To make a weather cock
(c) To breathe for survival
(d) For burning of substance
(e) For photosynthesis

9. How do plants and animals help each other in exchange of gases in the atmosphere?
Ans: Animals and plants use oxygen from air during respiration and release carbon dioxide gas in air. But green plants also release oxygen gas by using carbon dioxide during photosynthesis. Thus, we can say that animals and plants help each other in exchange of gases.

Class 6 Science Chapter 15 VERY SHORT ANSWER TYPE QUESTIONS

1. Name the main component of air.
Ans: Nitrogen gas

2. What is the source of oxygen gas in air?
Ans: Photosynthesis by green plants is source of oxygen gas in air.

3. What is the percentage of nitrogen in air?
Ans: 78.1%

4. What is the percentage of oxygen in air?
Ans: 20.9%

5. What is the source of carbon dioxide in air?
Ans: Respiration by animals and plants and burning of fuel.

6. Mention one necessary condition for the combustion to take place.
Ans: Presence of air.

Class 6 Science Chapter 15 SHORT ANSWER TYPE QUESTIONS

1. Why is air considered as a mixture?
Ans: Air contains oxygen and nitrogen as its major constituents of air. These gases retain their properties in air. So the air is called a mixture.

2. Name the major gas present in the (a) inhaled air (b) exhaled air.
Ans: (a) Oxygen     (b) Carbon dioxide.

3. Write the necessary conditions for rusting of iron to take place.
Ans: Rusting of iron takes place in the presence of moisture and air. So the presence of air and water vapour in air are two necessary conditions for rusting of iron.

4. Name a device which uses wind energy to generate electricity.
Ans: Windmills use the wind energy to convert wind energy into electrical energy

5. What is wind energy? Mention its two advantages.
Ans: Blowing air is called wind. Wind possesses kinetic energy. The kinetic energy possessed by wind is called wind energy.
Uses of Wind Energy are:
(i) Wind energy is used to pump the ground water.
(ii) Wind energy is used to generate electricity with the help of windmills.

6. Mention two uses of air.
Ans: The two uses of air are as below:
(a) For respiration all organisms need air.
(b) For burning of any substance air is needed.

7. Describe balance of oxygen in the air.
Ans: The oxygen in air is used by the organisms present in air, water or soil or on earth for their respiration. During respiration carbon dioxide gas is released to air. But green plants during photosynthesis use carbon dioxide of air for preparing food and they release oxygen gas in the air. Thus the balance of oxygen in air is maintained.

8. What happens if the percentage of oxygen in the air reaches to 70%?
Ans: If any substance catches fire it will become difficult to extinguish the fire, as oxygen supports combustion.

9. What happens if the percentage of carbon-dioxide increases in the air?
Ans: The increased percentage of carbon-dioxide will cause green house effect, i.e. it will not allow the hot rays of sun to escape from the atmosphere after reflection once they enter the earth’s atmosphere, thereby increasing the temperature of earth, ice on mountains will melt and water level will rise.

10. You must have seen during rainy season, when it rains the animals like earthworm, snakes, snails etc. are commonly seen. Explain why?
Ans: All these animals live in underground burrows or remain buried in the soil. They get oxygen from air that enters into the burrow through entrance of burrow or through pores in the soil. But when it rains, the water gets filled in their dwelling places and pores of the soil. So, they come out in search of air.

11. Why is carbon-dioxide gas used to extinguish fire?
Ans: It is because carbon-dioxide does not support combustion. When sprayed on burning object it stops the supply of oxygen and extinguishes fire.

12. How will you prove that soil contains air in it?
Ans: Take a glass tumbler add some soil in it, then pour some water on the soil slowly, the air-bubbles comes out of the soil. This proves that soil holds air in it.

13. Why do we see the sky and air clear and clean after rainfall?
Ans: The dust particles which remain suspended in air get loaded and come down on the ground due to rainfall, this is the reason that the sky and the air look clean and clear after rainfall.

14. Explain why mountaineers carry oxygen cylinders with them?
Ans: As you go up, above the sea-level the atmospheric pressure goes on decreasing and the amount of oxygen also decreases at higher altitude.

15. Explain why during an incident of fire, one is advised to wrap a woollen blanket over a burning object.
Ans: Blanket cuts the supply of oxygen to the object that is burning, thereby prevents it from further burning.

Class 6 Science Chapter 15 LONG ANSWER TYPE QUESTIONS

1. What is air? Name the major constituents of air. Also give their volume proportions in air.
Ans: Air is a mixture of gases. The major constituents of air are nitrogen, oxygen, carbon dioxide and argon. The percentage composition of constituents of air are as given below:

Other components of air are water vapour and dust particles.

2. Demonstrate through a simple experiment that the air mainly contains nitrogen and oxygen in the volume ratio of 4: 1.
Ans: Aim of experiment: To show that air contains nitrogen and oxygen in the ratio 4 : 1 by volume:
Procedure: Take a glass container and fix a candle at its centre. Put some quantity of water in the container. Place an empty, dry gas jar over it. Mark five marks above water surface on the jar at equal distances shown in the figure given below.

The candle is lightened and is covered with the gas jar. After some time the candle is extinguished and the water level is raised in gas jar. The raised level in water is 1 / 5 of the volume of air in the gas jar.
This proves that one part of the air of the jar is a gas which supports combustion, i.e., oxygen. Hence, 1/5 by volume is oxygen in air.

3. Air is a mixture. Prove this statement.
Ans: The components of mixture can be easily separated and they retain their properties.

The components of air are: oxygen, nitrogen, water vapour and carbon-dioxide, all these gases can be easily separated and they retain their properties.

NCERT Solutions

NCERT Solutions for Class 6 Science Chapter 14 Water

Topics and Sub Topics in Class 6 Science Chapter 14 Water:

Section Name	Topic Name
14	Water
14.1	How much water do we use?
14.2	Where do we get water from?
14.3	Water cycle
14.4	Back to the oceans
14.5	What if it rains heavily?
14.6	What happens w it does not rain for a long period?
14.7	How can we conserve water?
14.8	Rainwater harvesting
14.9	Summary

 1. Fill up the blanks in the following:
(a) The process of changing of water into its vapour is called_______________ .
(b) The process of changing water vapour into water is called_____________ .
(c) No rainfall for a year or more may lead to _____________ in that region.
(d) Excessive rains may cause__________ .
Ans:
(a) evaporation or vaporisation
(b) condensation
(c) droughts
(d) flood

2. State for each of the following whether it is due to evaporation or condensation:
(a) Water drops appear on the outer surface of a glass containing cold water.
(b) Steam rising from wet clothes while they are ironed.
(c) Fog appearing on a cold winter morning.
(d) Blackboard dries up after wiping it.
(e) Steam rising from a hot girdle when water is sprinkled on it.
Ans: 
(a) condensation
(b) evaporation
(c) condensation
(d) evaporation
(e) evaporation.

3. Which of the following statements are “true”?
(a) Water vapour is present in air only during the monsoon.
(b) Water evaporates into air from oceans, rivers and lakes but not from the soil.
(c) The process of water changing into its vapour is called evaporation.
(d) The evaporation of water takes place only in sunlight.
(e) Water vapour condenses to form tiny droplets of water in the upper layers of air where it is cooler.
Ans: 
(a) False
(b) False
(c) True
(d) False
(e) True.

4. Suppose you want to dry your school uniform quickly. Would spreading it near an anghiti or heater help you? If yes, how?
Ans: Yes, to dry the school uniform quickly, the uniform is spread near an anghiti or heater because evaporation is rapid at higher temperature. Higher the temperature faster is the rate of evaporation. So the uniform is dried up quickly.

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?
Ans: The cooled water bottle has very cold exposed surface. Due to cool surface there is condensation of water-vapour from air on the surface of water bottle because water vapour is present in atmosphere. The condensed water molecules spread around the bottle. So a puddle of water is noticed after sometime.

6.To clean their spectacles, people often breathe out on glasses to make them wet. Explain why the glasses become wet?
Ans: The breathe out gases contain water-vapour. The water-vapour condenses at spectacles so glass becomes wet and with the help of small amount of water, it is easy to clean the spectacles.

7. How are clouds formed?
Ans: The water present on the earth evaporates due to heating by the sun. The water vapour in the air condenses to form tiny droplets of water at high altitude, which appears as clouds. Thus clouds are formed by the condensation of water vapours present in air at high altitude.

8. When does a drought occur?
Ans: If there is no rain for a long period or for many years then there is scarcity of water in that region. This leads to drought.

Class 6 Science Chapter 14 VERY SHORT ANSWER TYPE QUESTIONS

1. Write the sources of water on the earth.
Ans:  Sources of water on the earth are:
Seas, Oceans, Rivers, Springs, Tubewells, etc.

2. In which forms, water exists on the earth?
Ans: Water exists on the earth in all three physical forms: ice, water and water vapour.

3. What is transpiration?
Ans: Loss of water in the form of water vapour through stomata of leaves is called transpiration.

4. How are the clouds formed?
Ans: Clouds are formed by the condensation of water vapour at high altitude.

5. What is meant by the conservation of water?
Ans: Careful, economical and wise use of water and avoiding the wastage of water is called conservation of water.

Class 6 Science Chapter 14 SHORT ANSWER TYPE QUESTIONS

1. Mention two main functions of water for living organisms.
Ans: Two main functions of water for living organisms are:
1. Water is essential for the germination of seeds, growth of plants and in photosynthesis.
2. Water is used for the transportation of people and goods.

2. Why is ocean water not suitable for domestic use?
Ans: Sea and ocean water contains large amounts of various salts. It is due to these salts the ocean water is salty and cannot be used for drinking, washing and for irrigation purposes.

3. Why does the water split on the floor disappear after some time?
Ans:  Due to evaporation the water split is changed into water vapour. So it disappears after some time.

4. How does heavy rain affect us?
Ans: Heavy rains may cause:
1. A rise of water level in dams, rivers, lakes, etc.
2. Waterlogging and floods.
3. Floods cause damage to property, crops and animals.

5. How does the failure of rainfall affect people on the earth?
Ans: The failure of rainfall can cause the following:
1.The soil becomes dry.
2. Water level in rivers, lakes, dams, etc. may fall. Ponds and canals may even dry up.
3. The ground water level falls.

6. Name two processes responsible for the formation of clouds.
Ans:  Evaporation and transpiration.

There are 4 containers A, B, C and D with same amount of water in each. Answer the following based on them.
(a) Name the container in which water will evaporate faster than all others.
(b) Name the container in which water will evaporate very slowly.
Give reason for your answer.
Ans.
(a) C – More is the exposed surface area, more will be evaporation of water.
(b) B – As it is closed, no evaporation takes place.

8. During winters why do we see more fog in close areas where there are lots of .trees?
Ans:  Due to lots of trees, air at that place contains much more water vapour during winters. These vapour condense on dust or smoke particles forming thick fog.

Class 6 Science Chapter 14 LONG ANSWER TYPE QUESTIONS

1. What is meant by conservation of water? Suggest three methods to conserve water.
Ans:  Careful and economical use of water and avoiding its wastage is called conservation of water.
Suggestions for conserving water:

1. Use only the required quantity of water.
2. Trees and forests help in causing rainfall. So to conserve water, we should plant more and more trees.
3. By collecting rainwater in tanks, ponds or by constructing check dams.

2. What is rainwater harvesting? Describe the method of rainwater harvesting.
Ans: Rainwater harvesting is the collection of rainwater and storing for future use. In this system rainwater in collected from the rooftops by means of pipes into storage tank for later use.
Methods of Rainwater Harvesting:

1. Rooftop rainwater harvesting. In this system, the rainwater from the rooftop is collected in a storage tank, through pipes.
2. Another method, a big pit is dug near house for collecting rainwater. This pit is filled with different layers of bricks, coarse gravels and sand or granite pieces.

NCERT Solutions

NCERT Solutions for Class 6 Science Chapter 13 Fun with Magnets

Topics and Sub Topics in Class 6 Science Chapter 13 Fun with Magnets:

Section Name	Topic Name
13	Fun with Magnets
13.1	Magnetic and non-magnetic materials
13.2	Poles of magnet
13.3	Finding directions
13.4	Make your own magnet
13.5	Attraction and repulsion between magnets

1. Fill in the blanks in the following:
(i) Artificial magnets are made in different shapes such as_________ ,_______ and
(ii) The materials which are attracted towards a magnet are called_________
(iii) Paper is not a________
(iv) In olden days, sailors used to find direction by suspending a piece of
(v) A magnet always has ________poles.
Ans:
(i) bar magnet, horse-shoe magnet and cylindrical magnet
(ii) magnetic materials
(iii) magnetic
(iv) bar magnet or lode stone
(v) two or a pair of

2. State whether the following statements are true or false:
(i) A cylindrical magnet has only one pole.
(ii) Natural magnets were discovered in Greece.
(iii) Similar poles of a magnet repel each other.
(iv) Maximum iron filings stick in the middle of a bar magnet when it is brought near them.
(v) Bar magnets always point towards North-South direction when suspended freely in air.
(vi) A compass can be used to find East-West direction at any place.
(vii) Rubber is a magnetic material.
Ans: 
(i) False
(ii) True
(iii) True
(iv) False
(v) True
(vi) True
(vii) False

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.
Ans:  Iron is used to make some part of sharpener due to which it is attracted toward magnet.

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.

Ans:

5. Write any two properties of a magnet.
Ans:  Two properties of magnets are:
(i) A magnet has two poles: North pole and South pole.
(ii) Like poles repel each other and unlike poles attract each other.

6. Where are poles of a bar magnet located?
Ans: Poles are located at the ends of bar magnet just before the ends. These are north and south poles.

7. A bar magnet has no markings to indicate its poles. How would you find out near which end is its north pole located?
Ans: Take the bar magnet and suspend it freely with the help of a thread, the end that points towards north pole will be regarded as north end of the magnet. Take a bar magnet with known/marked poles on it. Let the north pole of the magnet be brought closer to the suspended magnet at the end that is pointing towards north, if it shows repulsion than it is confirmed.

8. You are given iron strip. How will you make it into a magnet?
Ans:  Making a magnet: Take an iron strip and place it on the table. Now take a bar magnet and place one of its poles near one edge of the strip of iron. Without lifting it move it along the length of the iron strip till you reach the other end. Now lift the magnet and bring the pole to the same point of strip from where yob began. Repeat this process about 30-40 times. Bring some iron fillings near the strip and observe that the strip attracts the fillings. This indicates that the iron strip becomes magnet.
Remember that the pole of magnet and direction of its movement should not change.

9. How is compass used to find direction?
Ans: A compass is a small case of glass. A magnetised needle is pivoted inside the box. The needle can rotate freely. Compass also has a dial with directions marked on it. The compass is kept at the place where we want to know the directions. When the needle comes to rest it indicates north-south direction. The compass is then rotated until the north and south marked on the dial are at the two ends of the needle. Usually different colours are used to point the ends of needle to identify the north and the south poles.

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

Ans:

Class 6 Science Chapter 13 VERY SHORT ANSWER TYPE QUESTIONS

1. Name the compound of iron contained in lode stone.
Ans: The compound of iron is iron oxide or magnetite.

2. Name the shepherd after which magnet was named.
Ans: Magnets.

3. How can you separate a magnetic substance from a mixture?
Ans: By using a bar magnet, the magnetic substance is separated from mixture.

4. At which place on a magnet, its magnetic force is maximum?
Ans: At poles.

5. In which direction does a suspended magnet come to rest?
Ans: Magnet comes to rest in N-S (north-south) direction.

6. What happens when N-pole of a magnet is brought near the N-pole of a suspended magnet?
Ans: There is repulsion between these two magnets as there is repulsion between like poles.

Class 6 Science Chapter 13 SHORT ANSWER TYPE QUESTIONS

1. Draw the diagram of (a) Bar magnet (b) Horse-shoe magnet.
Ans:

2.Identify magnetic and non-magnetic substances from the list given below: Iron, Steel, Nickel, Plastic, Wood, Copper and a Stainless Steel spoon
Ans:

3. Draw a diagram of a magnetic compass.
Ans:

4. Write main properties of a magnet.
Ans: (i) Magnet has two poles—south pole and north pole.
(ii) Poles of magnet cannot be isolated.
(iii) Like poles repel each other and unlike poles attract each other.
(iv) Freely suspended magnet aligns in N-S direction.

5.Write two methods by which a magnet can be demagnetised.
Ans: (1) By hammering the magnet strongly.
(2) By heating a magnet strongly and keeping it in the east-west direction.

6. It is advised to keep the magnets away from television, mobiles, CD and computers Explain why?
Ans: Television, mobiles, CD, computers and many more devices are made up of magnetic materials and magnets in it. If you bring a magnet closer to it then it will spoil these devices.

7. Few iron nails and screws got mixed with the wooden shavings while a carpenter was working with them.How can you help him in getting the nails and screws back from the scrap without wasting his time in searching with his hands?
Ans: With the help of a magnet we can attract all iron nails and screws and can separate them from the wooden shavings. As iron nails and screws are magnetic materials and will get attracted to the magnet,whereas wooden shavings are non-magnetic.

8. It is said that repulsion is a sure test for magnetism. Why is it so?
Ans: To identify the magnet, repulsion (like poles of two magnets repel) is the only test which will let you know whether the given rod is an iron rod or a bar magnet. Because a magnet attracts an iron object and unlike poles of magnets also attract each other.

9. A given bar magnet was broken into pieces. Where will be its North and South pole?

Ans: If you cut a bar magnet into pieces then the end labelled as North remains north and the other end formed will be south. Similarly the end that was pointing south will be south pole and its opposite end will be the new north pole.

10. You are given two rods. Out of these, one is an iron rod and the other one is magnet, how will you identify these rods?
Ans: Take both the rods and suspend them separately. Bring one end of a bar magnet close to both the ends of the suspended rod. If it shows attraction at both the ends then it is an iron rod. If it shows attraction at one end and repulsion at the other end then it is a bar magnet.

Class 6 Science Chapter 13 LONG ANSWER TYPE QUESTIONS

1. Show that a magnet has two poles. What are the properties of the poles of a magnet?
Ans. We know that pole is the point where the strength of the magnet is maximum. So more and more iron particles will be attracted at poles of a magnet when we bring a magnet near the iron particles. We will observe the crowdness of particles at the ends of magnet. This indicates the presence of two poles in a magnet. Hence poles are present in a magnet in pair. If a magnet is divided into two parts, each part also possesses a pair of poles.

 NCERT Solutions

Topics and Sub Topics in Class 6 Science Chapter 12 Electricity and Circuits:

Section Name	Topic Name
12	Electricity and Circuits
12.1	Electric cell
12.2	A bulb connected to an electric cell
12.3	An electric circuit
12.4	Electric switch
12.5	Electric conductors and insulators

NCERT Solutions for Class 6 Science Chapter 12 Electricity and Circuits

1. Fill in the blanks:
(a) A device that is used to break an electric circuit is called_______________
(b) An electric cell has___________
Ans:
(a) switch
(b) two

2. Mark ‘True’ or ‘False’ for the following statements:
(a) Electric current can flow through metals.
(b) Instead of metal wires, a jute string can be used to make a circuit.
(c) Electric current can pass through a sheet of thermocol.
Ans:
(a) True
(b) False
(c) False.

3.Explain why the bulb would not glow in the arrangement shown in fig

Ans: The bulb would not glow in the arrangement shown in figure because the one end of tester/screw driver is made up of plastic which does not allow the electric current to flow through it.

4. Complete the drawing shown in Fig. 12.9 to indicate where the free ends of the two wires should be joined to make the bulb glow.

Ans:

5. What is the purpose of using an electric switch? Name some electrical gadgets that have switches built into them.
Ans: Electric switch is used to make electric circuit open or closed for a particular appliance and hence with the help of a switch we can use an appliance according

6. Would the bulb glow after completing the circuit shown in Fig. 12.9 if instead of safety pin we use an eraser?
Ans: No, since eraser is an insulator so it does not allow the current to pass. Hence the bulb will not glow.

7. Would the bulb glow in the circuit shown in Fig. 12.11.

Ans: Yes, the electric circuit is closed so the bulb will glow.

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.
Ans: Yes, if the object is good conductor of electricity then current will pass through conduction tester and the bulb will glow. Hence the object will be a conductor of electricity.

9. Why should an electrician use rubber gloves while repairing an electric switch at your home? Explain.
Ans: Our body is good conductor of electricity and rubber is insulator. During repairing work if the body comes in contact with current carrying wire then there will not be any accident as rubber does not allow the passage of current through it. Hence electrician uses rubber gloves while repairing an electric switch.

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?
Ans: Plastic or rubber is an insulator which does not allow electric current to pass through it. The handles of the tools like screwdrivers and pliers used by electricians for repair have covering of plastic or rubber so that electric current may not pass through these tools to the body of the electrician to harm him.

Class 6 Science Chapter 12 VERY SHORT ANSWER TYPE QUESTIONS

1. What is the direction of flow of current in a dry cell?
Ans: . The current flows in closed circuit from +ve to -ve terminal of cell.

2. Name the +ve terminal of dry cell.
Ans:. Carbon rod with a metal cap on it.

3. Name the -ve terminal of a dry cell.
Ans:  Zinc metal plate.

4. What is dry cell?
Ans:  It is a device which converts chemical energy into electrical energy.

5. What is solar cell?
Ans: A device which converts solar energy into electrical energy.

6. What is open circuit?
Ans:  An electric circuit in which electrical contact at any point is broken is called open circuit.

7. Write one use of insulators.
Ans: Insulators are used in making switchboard, handles of testers, screw drivers.

8. What is the name of thin wire in the electric bulb?
Ans: Filament.

Class 6 Science Chapter 12 SHORT ANSWER TYPE QUESTIONS

1. Mention two advantages of a dry cell.
Ans: 
1. It converts chemical energy into electrical energy.
2. It is light and small in size.

2. Draw a diagram showing the two terminals of a bulb.
Ans:

3. Draw the circuit diagram for operating a bulb with the help of a dry cell.
Ans:

4. Define conductors and insulators. Give one example of each.
Ans:  A conductor is that which easily allows the passage of current through it. Example: Aluminium or any metal.
An insulator is that which does not allow the passage of current through it. Example: Rubber.

5. Identify conductors and insulators from the following:Eraser, paper, matchstick, copper wire, pencil lead, polythene
Ans: Conductors: Copper wire, pencil lead.
Insulator. Eraser, paper, matchstick, polythene.

6. Name the scientist who invented electric cell and the scientist who invented electric bulb.
Ans: Electric cell: Alessandro Volta.
Electric bulb: Thomas Alva Edison.

7. Give one activity to prove that air is an insulator.
Ans: Take an electric circuit, keep the terminals unconnected in the air. The bulb do not glow, as air is an insulator and does not allow the current to flow through it.

8. In any electric circuit, when the switch is on and the current flows through it why do the wire, switches, bulb or devices become hot?
Ans.: This is because electric energy changes into heat energy.

9.The headlights of a car have reflectors behind the bulb. What is the function of reflectors?
Ans: The reflector helps in reflecting the light into a focussed area.

10.If you touch an electric wire carrying current you get a shock, but if on the same wire the birds sit they do not get any shock/current. Explain why?
Ans: When we hold the wire carrying current then the circuit is closed and the current flows from our body and enters earth but the birds sitting on the same wire do not get any current as the circuit is not complete. If the bird touches the earth wire, it will also die due to electric shock.

Class 6 Science Chapter 12 LONG ANSWER TYPE QUESTIONS

1.(1)What is electric circuit?
(2)How many types of electric circuit are there? Define them.
(3)Draw a diagram to show the closed circuit for switch, bulb and dry cell.
Ans: 
(1)The diagram that shows the path of electric current is called electric circuit.
(2)There are two types of electric circuit:
(a) Open electric circuit
(b) Closed electric circuit
(a)Open electric circuit: The circuit in which electrical contact at any point is broken is called open electric circuit.
(b)Closed electric circuit: The circuit in which electric current flows from one terminal of a cell or battery to the other is called a closed circuit.

NCERT Solutions