Page 180 - Science Class 07

4. Metallic wastes such as lead oxide, mercury, etc. are easily decomposed
by the micro-organisms.
5. Open drains or sewage are the breeding ground for flies, mosquitoes and
other micro-organisms.
E. Very short answer ques ons.

1. What are wastes?
2. What do you mean by management of wastes?
3. What are biodegradable wastes?
4. Give examples of solid wastes discarded from homes.

5. What is sewage?
6. Name any four diseases which are caused due to use of contaminated water.
F. Short answer ques ons.
1. Write any four basic objec ves of waste management.

2. Differen ate between biodegradable and non-biodegradable wastes.
3. Write important sources of solid, liquid and gaseous wastes.
4. Write harmful effects of sewage.

5. What is sewage treatment?
G. Long answer ques ons.
1. Explain waste management in your own words.
2. How can you classify the wastes? Explain.

3. What are solid waste, liquid waste and gaseous waste?
4. Describe the process of sewage treatment.

Project ActivityActivityActivity
Project
Project
Project Activity
A. Make a list of biodegradable and non biodegradable wastes generated at your home. Find out
their weight separately. Now, find out es mated weight of wastes generated in your locality
and in your city.

B. Make posters to encourage people for reuse and recycling of wastes. Also make them know
about the recyclable and non-recyclable wastes.

HOTSTSTS
HO
HO
HOTS
A. How do faulty sewer lines increase the risk of water-borne diseases?
B. Which pipes should be bigger — those used for sewage disposal or those used for storm water
disposal? Why?

C. Why do we feel the need for conserva on of water more today them our ancestors did?

180 Science-7