The DAV Class 4 Science Book Solutions and DAV Class 4 Science Chapter 10 Question Answer – Water Pollution are essential study tools for DAV public school students in Class 4.
DAV Class 4 Science Chapter 10 Question Answer – Water Pollution
DAV Class 4 Science Ch 10 Question Answer – Water Pollution
Something To Know
A. Fill in the blanks.
Question 1.
______ is the purest form of water.
Answer:
Rainwater
Question 2.
Water containing impurities is called ______ water.
Answer:
Polluted
Question 3.
Chemical fertilizers and ______ used by farmers cause water pollution.
Answer:
Pesticides
Question 4.
Drinking ______ water cause diseases like diarrhea and jaundice.
Answer:
Polluted
Question 5.
______ and agricultural wastes increase the growth of micro-organisms in water.
Answer:
Industrial.
B. Write True or False for the following statements.
1. River water is the purest form of water.
2. Polluted water may contain dust, germs and smoke.
3. Throwing domestic waste in rivers causes water pollution.
4. Increased growth of micro-organisms in water increases the amount of oxygen for aquatic animals.
5. Use of chemical fertilizers helps in preventing water pollution.
Answer:
1. River water is the purest form of water. (False)
2. Polluted water may contain dust, germs and smoke. (True)
3. Throwing domestic waste in rivers causes water pollution. (True)
4. Increased growth of micro-organisms in water increases the amount of oxygen for aquatic animals. (False)
5. Use of chemical fertilizers helps in preventing water pollution. (False)
C. Tick (✓ ) the correct option.
1. A disease that may be caused by drinking polluted water is
(a) malaria
(b) cough
(c) cholera
(d) dengue
Answer:
(c) cholera
2. Polluted water should not be used for irrigation because
(a) It can harm aquatic animals
(b) It pollutes river water
(c) It reduces fertility of soil
(d) It increases the production of crops
Answer:
(c) It reduces the fertility of soil
3. Oil spills in the sea are harmful because they
(a) decrease the level of water in sea
(b) infect the aquatic plants
(c) increase the growth of micro-organisms in water
(d) cut off the supply of oxygen for aquatic animals
Answer:
(d) cut off the supply of oxygen for aquatic animals
4. Pollution of river water can be reduced if
(a) chemical fertilizers are used for increasing production of crops
(b) farmers use sprinklers for irrigating their fields
(c) water is allowed to stagnate around the river banks
(d) people do not wash clothes or bathe their cattle in rivers
Answer:
(d) people do not wash clothes or bathe their cattle in rivers
D. Answer the following Questions in brief.
Question 1.
Name any two materials which can make rain water impure.
Answer:
Dust and smoke
Question 2.
Name any two human activities which can cause water pollution.
Answer:
Washing clothes in rivers and bathing in rivers
Question 3.
Which two pollutants are often dumped by the factories into the rivers?
Answer:
Harmful chemicals and solid waste materials
Question 4.
Name any two diseases that may be caused by drinking polluted water.
Answer:
Jaundice and cholera
Question 5.
Write the names of two types of materials, used by farmers, to increase the production of crops.
Answer:
Fertilisers and pesticides
E. Answer the following Questions.
Question 1.
How do wastes, from factories and fields affect the aquatic animals?
Answer:
Agricultural waste and industrial waste increase the growth of microorganisms in water. This reduces oxygen supply for the aquatic animals and thus harms them.
Question 2.
How can polluted water affect the crops?
Answer:
When polluted water is used for irrigation, it damages the crops and reduces soil fertility. Thus, polluted water affects the crops.
Question 3.
Why are oil spills harmful for marine life?
Answer:
Oil spills create a layer of oil on top of water. This layer prevents oxygen from reaching the aquatic animals. Thus, it becomes difficult to live for the marine life. Hence, oil spill is harmful for marine life.
Question 4.
State any four effects of water pollution.
Answer:
Following are four effects of water pollution:
- Poisonous chemicals from factories kill marine animals.
- Industrial and chemical wastes increase the growth of microbes in water. This reduces oxygen supply for aquatic animals.
- Oil spills form a cover on the surface of water. This cuts off oxygen supply to aquatic animals.
- Drinking polluted water may cause diseases like typhoid, diarrhea, cholera and jaundice.
Question 5.
State four ways of reducing water pollution.
Answer:
Prevention of Water Pollution:
1. Wastes from factories should not be allowed to flow into rivers without prior purification.
2. Sewage pipes should be kept away from pipes carrying drinking water.
3. Sewage line should be prevented from entering into wells or rivers.
4. Bathing and washing in rivers should be prevented.
Value Based Questions
Question 1.
State the values displayed by Ria.
Answer:
Ria showed concern for river pollution and environmental degradation.
Question 2.
Suggest some ways of disposing off the ‘pooja’ materials.
Answer:
The ‘pooja’ materials can be disposed off at the base of a tree. After some time, the materials will turn into compost because of decomposition.
Something To Do
Question 1.
Make a collage showing various ways in which water gets polluted.
Answer:
Do it yourself.
Question 2.
Make posters, and write slogans, on prevention of water pollution. Display them in the school.
Answer:
Do it yourself.
Question 3.
Read the hints given below and fill in the boxes in the crossword puzzle with suitable words.
Across:
2. It is the name of a disease caused by drinking polluted water.
4. This water when mixed with rivers or wells makes them polluted.
Down:
1. They increase the production of crops but cause water pollution
3. This material may be present in polluted water.
5. Oil spills reduce the supply of this gas for aquatic animals.
DAV Class 4 Science Chapter 10 Solutions – Water Pollution
I. Multiple Choice Questions.
1. Which of the following is the purest form of water?
(a) Rain water
(b) River water
(c) Pond water
(d) Lake water
Answer:
(a) Rainwater
2. Oil spill is caused by which of the following?
(a) Ship
(b) Oil tanker
(c) Boat
(d) Yacht
Answer:
(b) Oil tanker
3. Which of the following activities can pollute river water?
(a) Boating
(b) Walking
(c) Bathing
(d) Swimming
Answer:
(c) Bathing
4. Growth of micro-organisms in a lake reduced the supply of which of the following for aquatic animals?
(a) Oxygen
(b) Nitrogen
(c) Water
(d) Carbon dioxide
Answer:
(a) Oxygen.
II. Fill in the blanks:
Question 1.
Poisonous chemicals from factories kill ______ animals.
Answer:
marine
Question 2.
Industrial wastes increase the growth of ______ in water.
Answer:
micro-organisms
3. Aquatic plants and animals become ______ in polluted water.
Answer:
infected
4. People should not be allowed to wash ______ in rivers.
Answer:
clothes
III. Answer the following Questions:
Question 1.
What is water pollution?
Answer:
The process by which water becomes polluted is called water pollution.
Question 2.
What is polluted water?
Answer:
Water containing impurities is called polluted water.
Question 3.
How can we prevent the wastes from factories from polluting river water?
Answer:
Wastes from factories should be properly purified before being allowed to flow into river. This will help in preventing water pollution in river.
DAV Class 4 Science Chapter 10 Notes – Water Pollution
→ Water Pollution: The process by which water becomes impure is called water pollution.
→ Polluted water: Water containing impurities is called polluted water.
→ Causes of Water Pollution:
- Bathing and washing clothes in rivers.
- Throwing domestic waste in rivers.
- Waste and harmful chemicals from factories are dumped in rivers.
- Water from drains and sewage goes into rivers.
- Increased use of chemical fertilizers and pesticides by farmers.
- Oil spill by tankers
→ Effects of Water Pollution:
- Poisonous chemicals from factories kill marine animals.
- Industrial and chemical wastes increase the growth of microbes in water. This reduces oxygen supply for aquatic animals.
- Oil spills form a cover on the surface of water. This cuts off oxygen supply to aquatic animals.
- Aquatic plants and animals become infected due to polluted water. When other animals eat these animals, they also become sick.
- Drinking polluted water may cause diseases like typhoid, diarrhea, cholera and jaundice.
- Using polluted water for irrigation damages crops and reduces soil fertility.
→ Prevention of Water Pollution:
- Wastes from factories should not be allowed to flow into rivers without prior purification.
- Sewage pipes should be kept away from pipes carrying drinking water.
- Sewage line should be prevented from entering into wells or rivers.
- Bathing and washing in rivers should be prevented.
- Farmers should minimize the use of chemical fertilizers and pesticides.