The DAV Class 5 Science Solutions and DAV Class 5 Science Chapter 10 Question Answer – Air are essential study tools for DAV public school students in Class 5.
DAV Class 5 Science Chapter 10 Question Answer – Air
DAV Class 5 Science Ch 10 Question Answer – Air
Something To Know
A. Fill in the blanks.
Question 1.
The two main gases present in the air are ______ and ______
Answer:
nitrogen, oxygen
Question 2.
Animals need ______ gas for breathing.
Answer:
oxygen
Question 3.
Plants use ______ gas to prepare their own food.
Answer:
carbon dioxide
Question 4.
The process, by which plants prepare their food, is called ______
Answer:
photosynthesis
Question 5.
______ gas, present in the atmosphere, protects us from the harmful rays of sunlight.
Answer:
ozone
Question 6.
Air, containing impurities, is called ______
Answer:
polluted air.
B. Write True or False for the following statements.
1. Pure air is colourless, odourless and tasteless.
2. An empty glass bottle contains air.
3. Air gets impure due to the presence of nitrogen gas.
4. Leaves of a plant look greener before rain.
5. Oxygen is required for burning.
Answer:
1. Pure air is colourless, odourless and tasteless. (True)
2. An empty glass bottle contains air. (True)
3. Air gets impure due to the presence of nitrogen gas. (False)
4. Leaves of a plant look greener before rain. (False)
5. Oxygen is required for burning. (True)
C. Tick (✓) the correct option.
1. The gas, which is present the most in air, is
(a) oxygen
(b) nitrogen
(c) carbon dioxide
(d) water vapour
Answer:
(b) nitrogen
2. An air pollutant, which exists in solid form, is
(a) sulphur
(b) nitrogen
(c) smoke
(d) ozone
Answer:
(c) smoke
3. The gas, whose amount varies with weather changes is
(a) nitrogen
(b) helium
(c) water vapour
(d) oxygen
Answer:
(c) water vapour
4. The gas, that gets reduced, through the process of photosynthesis, is
(a) sulphur oxide
(b) nitrogen oxide
(c) ozone
(d) carbon dioxide
Answer:
(d) Carbon dioxide
5. When sulphur dioxide reacts with water and oxygen in air, it results in the production of
(a) snow
(b) acid rain
(c) nitrogen oxide
(d) carbon dioxide
Answer:
(b) acid rain.
D. Answer the Following Questions in Brief.
Question 1.
Name the main components of air.
Answer:
Nitrogen, oxygen and other gases
Question 2.
State the meaning of the term ‘Photosynthesis’.
Answer:
The process by which plants make their own food is called photosynthesis.
Question 3.
State two possible harmful effects of ultraviolet rays.
Answer:
Two possible harmful effects of ultraviolet rays are as follows:
(a) It can cause skin and eye diseases
(b) It can damage crops
Question 4.
Define the term ‘Air pollutant’.
Answer:
Substances which can pollute the air are called air pollutants.
Question 5.
Name any two of the gaseous pollutants present in air.
Answer:
Carbon monoxide and oxides of sulphur and nitrogen.
Question 6.
List any four causes of air pollution.
Answer:
Four causes of air pollution are as follows:
(a) Smoke from automobiles
(b) Dust from stone quarries
(c) Dust from dust-storm
(d) Smoke from factories
E. Answer the following Questions.
Question 1.
Why is air necessary for animals?
Answer:
All animals need oxygen to live. All animals take oxygen during breathing. This oxygen is utilized by the body to produce energy. The oxygen comes from air. Thus, air is necessary for animals.
Question 2.
How is nitrogen important for plants?
Answer:
Nitrogen is essential for growth of plants. Plants need nitrogen in large amounts. Plants use nitrogen to make protein.
Question 3.
How is the balance of oxygen and carbon dioxide in air, maintained in nature?
Answer:
All animals use oxygen during respiration and give out carbon . dioxide. Plants take up carbon dioxide during photosynthesis and release oxygen. Thus, a balance between carbon dioxide and oxygen is maintained in the air.
Question 4.
Why is ‘acid rain’ harmful?
Answer:
The acid rain damages crops and 1 reduces fertility of soil. Acid rain also damages monuments and buildings.
Question 5.
Why should we feel ‘worried’ about ‘global warming’?
Answer:
Global warming is leading to melting of polar ice-caps. This can cause widespread destruction in the world. So we should be worried about global warming.
Question 6.
Suggest some ways of reducing air pollution.
Answer:
Ways to Reduce Air Pollution
- Plant more trees
- Reduce the use of vehicles
- Regular check up of vehicles.
- Use of cleaner fuels.
Question 7.
How does planting of trees help in making air cleaner?
Answer:
Trees utilize carbon dioxide during photosynthesis and release oxygen. Thus, trees purify the air. Thus, planting of trees help in making air cleaner.
Value Based Question
Question 1.
Do you agree with Reema and why?
Answer:
I agree with Reema because by pooling the car, there are clear I benefits. The most important benefit isthe protection of environment. Saving money is another benefit.
Question 2.
Would this practice of commuting to school help nature?
Answer:
By using the car-pool we can minimize the cars on the road. This will help in reducing air pollution and will help the nature.
Something To Do
Question 1.
Make a poster on ‘Go Green – to breathe clean’ using magazine pictures.
Answer:
Do it yourself.
Question 2.
Try to find out the answer to the following Questions:
(a) Why do plants look greener after rain?
Answer:
Rain washes all the dirt from the leaves. So, plants look greener after rain.
(b) Why are LPG and biogas called ‘cleaner fuels’?
Answer:
CNG does not produce smoke or ash on burning. So, it is environment-friendly and is called a better green fuel.
Question 3.
With the help of block diagram, explain the role of nitrogen, in the growth of plants.
Answer:
Do it yourself.
Question 4.
Power stations, which bum fossil fuels to produce electricity, are one of the main causes of increasing the amount of carbon dioxide in the air. One way, to reduce the air pollution caused by power stations, is to use less electricity. Suggest how you can try to make an effort to reduce electricity consumption in your home.
Answer:
Some of the ways to reduce electricity consumption in home:
- During the day, read at a place where lot of natural light comes.
- Switch off the fan and light when nobody is in room.
- Avoid using air-conditioner or air-cooler until the weather is too uncomfortable.
- Use LED instead of normal bulbs.
DAV Class 5 Science Chapter 10 Solutions – Air
I. Multiple Choice Questions (MCQs)
1. Which gas is responsible for green house effect?
(a) oxygen
(b) nitrogen
(c) hydrogen
(d) carbon dioxide
Answer:
(d) carbon dioxide
2. Which gas is required by plants while making protein?
(a) oxygen
(b) nitrogen
(c) carbon dioxide
(d) helium
Answer:
(b) nitrogen
3. Which gas protects us from harmful ultraviolet radiations?
(a) Helium
(b) Nitrogen
(c) Ozone
(d) Carbon dioxide
Answer:
(c) Ozone
4. Oxides of which gas make acid rain?
(a) nitrogen and sulphur
(b) nitrogen only
(c) sulphur only
(d) nitrogen, sulphur and helium
Answer:
(a) nitrogen and sulphur.
II. Fill in The Blanks
Question 1.
______ air is colourless, odourless and tasteless.
Answer:
pure
Question 2.
All animals need oxygen for ______
Answer:
respiration
Question 3.
Plants need ______ for respiration.
Answer:
oxygen
Question 4.
______ gas is released by animals after respiration.
Answer:
carbon dioxide
Question 5.
______ gas is released after photosynthesis.
Answer:
oxygen.
III. Define The Following
Question 1.
Acid rain
Answer:
When rainwater gets mixed with acidic gases, it is called acid rain.
Question 2.
Global warming
Answer:
General increase in average temperature on the earth is called global warming.
Question 3.
Greenhouse effect
Answer:
Trapping of solar radiation in the atmosphere to maintain the temperature on earth is called global warming.
IV. Answer The Following Questions
Question 1.
What is the importance of air?
Answer:
Importance of Air:
- All animals need oxygen to live. All animals take oxygen during breathing. This oxygen is utilized by the body to produce energy.
- Oxygen is required for burning objects.
- Plants also need air for respiration.
- Plants need carbon dioxide for making their own food by the process of photosynthesis.
Question 2.
Explain nitrogen fixation.
Answer:
Some bacteria, present in soil, convert the atmospheric nitrogen into specific forms (nitrate and ammonium salts). This process is called nitrogen fixation. Plants can easily absorb these salts from soil.
Question 3.
How does the atmosphere act like a shield?
Answer:
Our atmosphere acts like a shield. It prevents us from harmful rays of sunlight. Ozone gas is present in the upper layers of atmosphere. The ozone layer prevents harmful ultraviolet rays from reaching the surface of the earth. Ultraviolet rays can cause skin and eye diseases in animals and humans and can affect the growth of plants.
Question 4.
What are pollutants? Give some examples of solid and gaseous pollutants.
Answer:
The impurities are called pollutants. Carbon monoxide, ozone, oxides of nitrogen and sulphur, etc. are gaseous pollutants. Smoke, dust and germs are solid pollutants.