RBSE Solutions for Class 7 Science Chapter 17 Waste Management
RBSE Solutions for Class 7 Science Chapter 17 Waste Management
Rajasthan Board RBSE Class 7 Science Chapter 17 Waste Management
Text book Exercise
Choose the most appropriate option:
Question 1.
Which of the following has long disposal period?
(a) Banana Peelings
(b) Piece of wood
(c) Plastic bag
(d) Paper bag
Answer:
(c) Plastic bag
Question 2.
What happens when wastes (garbage) is thrown in open?
(a) Soil Pollution
(b) Water Pollution
(c) Air Pollution
(d) All above
Answer:
(d) All above
Fill in the blanks :
1. Biodegradable wastes with the help of bacteria are….in less time.
2. During our daily routine we throw unusable material. These unused materials are………..
3. Waste materials can be divided into solid ………….and ……….
4. Unnecessary products made up of plastic do not………. for longer period.
Answer:
- decomposed
- waste/garbage
- liquid, gaseous
- decompose.
Short Answer Type Questions
Question 1.
How can waste paper be made reusable?
Answer:
Waste paper can be made useful again by the recycling process. Waste paper is sent to recycling factories. Paper obtained after recycling can be used in different ways.
Question 2.
Enumerate the harm caused to environment by plastic/polythene etc.
Answer:
Polythene and plastics are non-bio degradable wastes. They are not decomposed for many years. They cause environmental pollution and destroy its beauty. Some times polythene bags are eaten by animals along with other waste materials. This causes their untimely death. The outlets of drains are blocked by polythene which leads to water over flow and water logging at different sites of city. Due to water logging many harmful microorganisms and mosquitoes breed and make human society sick.
Question 3.
How does garbage affect our health?
Answer:
Due to waste materials we get infected by various diseases like asthma, dengue, viral fever, malaria, cholera and several skin diseases etc. Because of the causative agents of these diseases breed in waste materials so, we should keep in mind that waste disposal should be done in appropriate way.
Question 4.
What are benefits of collecting domestic garbage in separate bins?
Answer:
Domestic waste materials are collected in separate containers on the basis of their nature by classifying as biodegradable or non biodegradable and then they can be disposed off appropriately.
For example: Manure is obtained from the domestic wastes like peels of fruits and vegetables, human excreta, animals dung and leaves of plants are decomposed. Manure so, obtained is used in agricultural field. In this way domestic waste is disposed and later on we get useful thing (manure) from it.
Question 5.
Which type of waste materials can be disposed off by recycle method?
Answer:
Waste materials like plastics and glass are disposed by re-cycling method. These are used in re-cycling factories to manufacture useful articles. During recycling some reagents are mixed to make bags, Packing bags, containers and sacs are made to store safe food materials.
Long Answer Type Questions
Question 1.
How will you manage household waste? Explain in detail.
Answer:
For the domestic waste management, three separate container should be kept at homes.
- Green colour container : For storing/ collecting biodegradable wastes like leaves, peels of fruits and vegetables, spoil food etc.
- Blue colour container : For collecting wastes like plastic materials, glass pieces, china pots etc.
- Black colour container : For collection of wastes like battery cells, unuseful medicines paints, oils, syringes and cosmetics etc.
By above method wastes can be managed and disposed off appropriately. By applying systematic disposal we can earn sufficient money in exchange of these wastes from Junk dealers.
Question 2.
What is the difference between biodegradable and non-biodegradable waste materials? Explain by example.
Answer:
1. Biodegradable waste : These waste materials are obtained from living organisms. These are decomposed by microorganisms. They produce manure.These materials are decomposed soon and mixed with soil.
For example: Plant leaves, peels of fruits and vegetables, waste paper, clothes, excreta, dung etc waste materials are called biodegradable wastes,
2. Non-Biodegradable wastes : These waste materials are manufactured in industries. These waste materials are not decomposed (degraded) by micro-organisms and these degraded wastes do not mix with the soil and create environmental pollution all around
For example: paints, glass pieces, metal pieces, plastic materials are non-biodegradable wastes.
Question 3.
What are the methods of disposal of the non biodegradable wastes? Explain.
Answer:
There are three-R methods of disposal of the non-bio-degradable wastes.
1. Reduce : It means to reduce the number/ amount of unuseful things like broken tin container, plastic bottles, container, broken earthen pots etc. These can be put into domestic use by growing flowers’ vegetables in them. The quantity of un-useful materials can be reduced by this way.
2. Reuse : It means use again and again. Separate such materials from domestics unuseful wastes, that
can be used again. For example : Battery, metal utensils, iron-rods, broken containers, glass bottle, jute materials etc. can be used again for some other domestic works.
3. Recycles : Plastic and glass wastes are sent to recycling factories after separating them from other unuseful wastes. In recycling factory new products are made during recycling. Some reagents are mixed to make new products. These materials (new products) are specially used to make bags. Packing bags, containers to store food materials safely.
Question 4.
What are the methods of disposal of biodegradable waste? Explain.
Answer:
The methods of disposal of Biodegradable wastes are given below.
1. Composting : In this method manure is prepared by decomposing of biodegradable materials like peels of fruits and vegetables, Excreta, animals, dung, plant leaves, grasses and other decompose materials. The type of material is put in a pit dug in a shady place in a comer and covered with soil in such a way that air is available and moisture is retained in the pit. After sometime this material is converted into manure by the action of micro organisms. Which can be used in field. This is called compost. The cattle dung (cows/buffalo) used in gobar gas plant is converted into manure after some time gobar gas is also produced which is used to light lamps and can also be used as feel in stoves of our kitchen.
2. Vermi Composting : In this method biodegradable waste disposal, Red earth worms are used which consume organic matter and form a high quality of manure. This is called vermi compost and the process is known as vermi composting.
3. Land filling : In this method, solid wastes are filled in big pit out side the town and covered with layer of soil. After some time these waste get degraded.
Activity
Question 1.
Prepare a research project on the impact of plastic bags on animal health.
Answer:
Now a days polythene bags are being used extensively causing harm to the environment and animals at a dangerous level. Polythene is non- biodegradable which is not destroyed by microorganism even in long duration. Some times animals consume polythene bags along with waste materials which adversely affect the digestive system of animals. They get accumulated in the body of animals because digestive enzymes do not affect polythene. Finally animals die before time. With the help of your teacher make an extensive survey on the effect of polythene on the health of animals do research on it. That is do systematic investigation into it and establish facts to reach new conclusions.
Question 2.
Prepare a research project on impact of plastic bags on water absorbing capacity of the soil.
Answer:
Polythene bags reduce the water absorbing capacity of the soil because of this sufficient amount of water is not available to the plants, which adversely effect plant health. With the help of your teacher investigate the affects of polythene on the water absorbing capacity of the soil. Survey the area and establish facts to reach new conclusion.
InText Questions
(Page 176)
Question 1.
What happens when plants wither ?
Answer:
Some parts of dry plants fall on the land. Which are decomposed by microorganisms present in the soil; They are converted into Humus. Humus makes the soil fertile. Some dry parts of the plants are used as domestic fuels.
Question 2.
Where does the sewage of your home go?
Answer:
Dirty water from our homes reach. Ponds, drainage, and later on to rivers through small drains.
Question 3.
What happens to the plastic materials that we throw out?
Answer:
Plastic materials are non biodegradable. These are not decomposed (not converted into simple and less harmful forms) by microorganisms. Therefore these materials create serious environmental pollution problem.
Question 4.
Dustbins are placed by municipal council, Zilla Parishads. Where is this waste carried and what is done of this waste?
Answer:
The waste materials are collected from dustbins and these are taken to waste disposal spot where these are disposed off systematically.
(Page-178)
Question 1.
Nowadays, under the Swatch Bharat Abhiyan hygienic toilets are being laid down in schools, villages and public places like markets
and along the side of roads. Have you ever thought why is this being done ? Why are they needed ?
Answer:
By constructing Toilets, human excreta is disposed off in an appropriate way. If it is not done, people will defecate in open, In such condition human excreta is scattered here and there and freely flown which pollute environment and people suffer from many communicable infectious diseases. It is necessarily needed.
Question 2.
What is the harm of open defecation?
Answer:
Defection in open causes environmental pollution and people suffer from infections and diseases.
Question 3.
You might have seen people defecating in open near railway stations, bus stands, around in slums and fields. Open defecation causes dirt and foul smell to spread which poll uses the environment with swarms of flies and mosquitoes. What are the adverse effects on the health of living beings living there ?
Answer:
The places of open defection are highly littered and full of foul smell makes the place unfit for living. Here flies and mosquito breed enormously and cause diseases. The health of animals and also human beings living there are adversely affected.
Hints : Students was discuss with their teacher concerned.
Activity 1: (Page-172)
Question 1.
What is waste?
Answer:
Those unwanted (unuseful) materials that we throw out in our day to day activities are called wastes.
Activity 2: (Page-173)
Question 1.
What are the main components of waste of Public Places?
Answer:
Plastics and Polythene.
Question 2.
Why safe disposal of hospital wastes is necessary?
Answer:
By safe disposal of hospital wastes, the possibilities of healthy persons from getting infected by diseases are almost finished and secured.
Activity 3: (Page-175)
Question 1.
Who is responsible for various types of water increasing on the earth?
Answer:
Undoubtedly We, human beings are responsible for increasing waste on the earth.
Question 2.
Why is man polluting his own environment?
Answer:
It is because, the love and affection of man has reduced very much towards his environment and has been using man made things instead of naturally available things and throwing out unuseful things out in open thus polluting own environment. Lack of wisdom and love to nature have led us to pollute our environment.
Activity 4: (Page-177)
Question 1.
Go to the shop of a kabadi (Ragman) and observe carefully, What Kabadies do of those useless things?
Answer:
Kabadies (Ragmen) separate different types of articles from those of unuseful materials. For example-They separate items, such as iron, copper, aluminium, papers, cardboards, note book, electronic wires, and plastic materials. They store them separately.
Question 2.
Where or to whoem Kabadei or Junk dealers, sell these items?
Answer:
Kabadei, after separating different types of unuseful material, send them to respective factories for their recycling work. These unuseful materials are transformed into a new product after recycling. The kabadies Junk dealers or Ragwen receive handsome money for their supplies.
Question 3.
What is Re-cycling?
Answer:
The process of converting un-useful material into useful materials is called Re-cycling.
Question 4.
For what types of waste disposal, the Recycling is a useful method?
Answer:
Recycling is a sub file method for the disposal of solid wastes.
Other Important Questions
Multiple Choice Questions
Question 1.
Biodegradable waste is:
(a) Leaves of plants
(b) Peels of fruits and vegetables
(c) Excreta-Dung
(d) All these
Answer:
(d) All these
Question 2.
Non biodegradable waste is:
(a) Paint
(b) Glass
(c) Metal pieces
(d) All these
Answer:
(d) All these
Question 3.
Waste released from Industries are:
(a) Solid wastes
(b) Liquid of wastes
(c) Gaseous wastes
(d) All these
Answer:
(d) All these
Question 4.
It is not a method of disposal of biodegradable wastes:
(a) Recycling
(b) Composting
(c) Vermi composting
(d) Lend filling
Answer:
(a) Recycling
Question 5.
Recycling is not possible for:
(a) Paper
(b) Plastic
(c) Wood
(d) Metals
Answer:
(c) Wood
Fill in the blanks :
1. Waste is the result of humans …….. and social activities.
2. Plastic and polythene are …………. wastes.
3. Biodegradable wastes are converted into …………. after decomposition.
4. Systematic or organised disposal of wastes is called ………..
Answer:
- natural
- non biodegradable
- humus
- waste management
Very Short Answer Type Question
Question 1.
What is waste?
Answer:
We throw out many unwanted and unuseful things as a result of our day to day activities. Such unwanted or un-necessary things are called wastes.
Question 2.
What are the types of wastes?
Answer:
- Biodegradable wastes
- Non biodegradable wastes.
Question 3.
Write the names of any four biodegradable wastes.
Answer:
- Plant Leaves
- Peels of fruits and vegetables
- Waste paper
- Clothes etc.
Question 4.
Write the names of any four Non- biodegradable wastes.
Answer:
- Paint
- Glass
- Metal pieces
- Plastic and polythene
Question 5.
Into how many groups, can wastes be classified on the basis of their physical state?
Answer:
- Solid wastes
- Liquid wastes
- Gaseous waste.
Question 6.
Give example of some solid wastes.
Answer:
- Plastic
- Pieces of glass
- Pieces of syringes.
Question 7.
Give some examples of liquid wastes.
Answer:
- Dirty water
- Oil
- Paint
- Sewage.
Question 8.
What are gaseous wastes?
Answer:
Smoke released from vehicles, Industries and factories is called gaseous waste.
Question 9.
How do polythene affect animals?
Answer:
Animals die un-natural death (untimely death) due to consumption of polythene bags along with other waste materials.
Question 10.
What is waste Management?
Answer:
The process of organised disposal of wastes, is called waste management.
Short Answer Type Questions
Question 1.
On what basis, waste is classified ?
Answer:
Waste materials are classified on the basis of their physical and chemical properties Mid uses. There are some materials in the wastes that can be reused, while there are some materials that can not be reused. On this basis wastes are classified as:
Biodegradable waste and Non biodegradable wastes.
Question 2.
Can, degradation (decomposition) of all kind of waste materials be in same time periods?
Answer:
No, duration of decomposition of different waste materials is different. Some materials are decomposed within 10 days, some in 4-5 months, some are decomposed in 4-5 years, some decomposes in 500 years and others like different types of plastics take Laths of years to decompose.
Question 3.
What is the cause of Environmental pollution?
Answer:
In present t;me (nowadays) our love and affection towards environmental conservation has reduced very much. We have been using man made things extensively in place of natural things as a result the beauty of nature has destroyed along with environmental pollution.
Question 4.
What is compost? How is it prepared?
Answer:
The manure (Khad) made from biodegradable substances like peels of fruits and vegetable, human excreta, cattle dung, plant leaves, grasses and other dead and decomposed materials is called compost. It is prepared by putting the biodegradable substances in a pit dug in a shady place.
Question 5.
What is vermi compost?
Answer:
Red earth worms consume organic matter when mixed with biodegradable substances. The excreta released by earth worm is a high quality of manure (Khad). This is called vermi compost and the process is known as vermicomposting.
Question 6.
What is 3R in waste disposal?
Answer:
The methods of waste disposal are called 3R. The meaning of 3R is as follows:
- Reduce : It means, use things in lesser amount or use when necessary.
- Reuse : It means use things again and again.
- Recycle : It means to make required things from wastes.
Question 7.
What is the Aim of Swachh Bharat Abhiyan?
Answer:
The Aim of Swachh Bharat Abhiyan is to make Bharat Swachh, That is neat and clean. Open defecation causes foul smell all around making the environment polluted. Also it spreads many infectious diseases. To get rid of this problem, under Swachh Bharat Abhayan, safe Toilets are being constructed in schools, villages and in each house of village, road sides and at public places.
Question 8.
Depict, Polythene generated problems’ through flow chart.
Answer:
Question 9.
What measures should we adopt in our every day life for waste disposal?
Answer:
- We should try to use, useful things from wastes again and again.
- Wastes should always be dumped in dustbins.
- If any person does not dump, wastes in collecting bins, we should try to make understand to do so.
Long Answer Type Questions
Question 1.
What is waste? In how many groups, wastes are classified? Write different methods of waste disposal.
Answer:
Waste : We throw out many unwanted and unuseful things in our day to day activities. These thing are called waste.
Types of wastes: wastes are classified into two groups.
(i) Biodegradable waste materials : These waste materials are decomposed by microorganism and form khad (manure) For example: leaves of plants vegetable and fruits peels, waste paper, cloth, excreta and animal dung etc.
(ii) Non-biodegradable : Those waste materials which are not decomposed by bacteria are called non-biodegradable wastes materials. These materials cause environmental pollution. Example: paint, glass, pieces of metas, plastic materials etc.
Methods of waste disposal:
1. Methods of disposal of biodegradable waste material:
- Composting
- Vermicompost
- Land filling
2. Methods of disposal of non-biodegradable waste materials:
- Reduce: use when necessary or use, less and judiciously.
- Reuse: Use/again and again
- Recycle : Make new things again from old matter.
Question 2.
What is sewage? why is it harmful to discharge untreated sewage into rivers or ocean?
Answer:
Sewage is waste water that flows in sewer after used in homes, industries, hospitals. Sewage includes rain water that flows through roofs, streets, roads which carries harmful substances during heavy rains. Sewage is waste water containing suspended excreta in it. Waste water is indicator of contamination.
In this way sewage is a complex mixture of suspended solid, organic and inorganic impurities, naturists, saprophytes, disease carrying bacteria and other micro organisms. That is why discharge of untreated sewage in to rivers or oceans is harmful.
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