Samacheer Kalvi 3rd Standard Science Book Solutions Term 3 Chapter 3 Air
I. Fill in the blanks using the given words:
(air, weight, raises, lungs, inhale)
Question 1.
Air has ____________ .
Answer:
weight
Question 2.
Things need ____________ for burning.
Answer:
air
Question 3.
The process by which we breathe in air is known as ____________
Answer:
inhale
Question 4.
The organ that helps us to breathe is ____________.
Answer:
lungs
Question 5.
When we breathe in air, the chest up ____________.
Answer:
raises
II. Write ‘T’ if True and ‘F’ if False:
Question 1.
Air is nowhere.
Answer:
False
Question 2.
Air fills the empty space.
Answer:
True
Question 3.
Clouds move because of the movement of air.
Answer:
True
Question 4.
A very strong wind is called gale.
Answer:
True
Question 5.
We release oxygen during breathing.
Answer:
False
III. Circle the odd one and answer the question:
Question 1.
Balloon, Cycle tube, Foot ball,Cricket ball
Answer:
Cricket ball
Why is it different from the rest?
Answer:
It does not contain air in it.
Question 2.
Kite, Balloon, Stone, Feather
Answer:
Stone
Why ______ differs from the rest?
Answer:
It differs from the rest, because it is heavy.
IV. Answer the following:
Question 1.
What are the properties of air?
Answer:
It has no definite shape and colour. Air has weight and it occupies space. We cannot see air but it can be felt. Air can flow everywhere.
Question 2.
Write the use of windmill.
Answer:
Electricity is generated from wind with the help of the windmills.
Question 3.
What is breathing?
Answer:
Inhalation is the process of taking the air inside and exhalation is the process of releasing the air outside. This cyclical process of inhalation and exhalation is called breathing.
Question 4.
Write the processes involved in breathing.
Answer:
The processes involved in breathing are inhalation and exhalation.
Question 5.
Write the types of wind based on the speed of air.
Answer:
Based on the speed of air, .wind can be classified as are breeze, strome & gale.
Question 6.
Differentiate between land breeze and sea breeze.
Answer:
Land breeze | Sea breeze |
1. The breeze that blows from the land towards the sea during night time | The breeze that blows from the sea towards the land during day time |
2. The warm air from the sea rises up and the cold air from the land moves towards the sea. | The warm air from the land rises up and the cold air from the sea occupies the space over the land |
InText Activity:
Warm-up (Text Book Page No. 92):
Observe the pictures and answer the given question.
What is necessary for these activities?
Answer:
Air
Try to answer (Text Book Page No. 94):
a. Write true or false for the following statements.
Question 1.
Air occupies space but has no weight.
Answer:
False
Question 2.
Air is colourless.
Answer:
True
Question 3.
Air has definite shape.
Answer:
False
b. If we fill air in the _________, it will change its shape.
(1) jar
(2) jug
(3) ball
Answer:
(3) ball
c. Which of the following ¡s required for good health?
(1) Dust
(2) Clean air
(3) Smoke
Answer:
(2) Clean air
Let us Try (Text Book Page No. 95):
Question 1.
Make a paper plane with waste paper and fly it in the air.
These activities conclude that air _________ the things.
Answer:
moves and pushes
Question 2.
Air is required for burning.
Light a candle and place it on a table. Now cover the lightning candle with a glass jar. Observe what. happens?
_________ is required for burning things.
Answer:
Air.
Let us Do (Text Book Page No. 96):
Air Jack
Materials required:
Empty plastic milk cover, a piece of thick string and an old pen body or pipe.
Procedure:
Tie an old pen body or a pipe to the mouth of the milk cover with a string. Place 3 or 4 thin note books up on the plastic milk cover and slowly blow air into it with your mouth. As the cover gets inflated the books get raised. How does that work? The pressure that you exert with your mouth is limited. But the large area of the milk cover magnifies this pressure and lifts the books.
The above activity shows that __________.
(1) Air rises up on getting warm
(2) Air is needed for burning
(3) Air has pressure
Answer:
(3) Air has pressure
Think zone (Text Book Page No. 97):
Why the doctor-in our chest raises up and when we breathe-out it lowers down.
Answer:
Doctor will usually check your pulse to counting your pulse rate, it is a simple way to find out how fast your heart ¡s beating.
Let us Do (Text Book Page No. 97):
Tick (✓) the one which breathes and cross (✗) the one that does not breathe.
Answer:
Let us Write (Text Book Page No. 97):
Choose and write the correct answer for the following actions.
Answer:
S. No. | Actions | Inhalation / Exhalation |
1 | Air moves out of the lungs | Exhalation |
2 | Air goes into the lungs | Inhalation |
3 | Chest raises up | Inhalation |
4 | Chest lowers down | Exhalation |
Try to Answer (Text Book Page No. 98):
The effect of exercise on breathing:
Mathi and Mozhi practised various exercises like walking, skipping and running. They counted the number of times they breathed in one minute after each exercise and recorded their results in the bar diagram:
Look at the bar diagram.
a. Which activity raised the breathing rate the most?
Answer:
Running
b. Which activity do you think exercises the heart muscle the least?
Answer:
Sitting
c. Write ‘T’ if True and ‘F’ if False.
Question 1.
They breathed more number of times when they were walking.
Answer:
(F)
Question 2.
They breathed less number of times when they were sitting.
Answer:
(T)
Question 3.
They took 50 breaths per minute when they were running.
Answer:
(T)
Question 4.
The more vigorous (active) the exercise, the greater the number of breaths.
Answer:
(T)
Let us connect (Text Book Page No. 100):
a. Breeze | Strong wind |
b. Storm | Very strong wind |
c. Gale | Gentle wind |
Answer:
a. Breeze | Gentle wind |
b. Storm | Strong wind |
c. Gale | Very strong wind |
Let us draw (Text Book Page No. 101):
Draw the movement of air for land breeze and sea breeze.
Answer:
Try to Answer (Text Book Page No. 101):
Fill in the blanks.
Question 1.
Gentle air is called __________.
Answer:
breeze.
Question 2.
We get electricity from wind using __________
Answer:
wind mills
Question 3.
The air that flows from the land towards the sea is __________
Answer:
Land breeze
Question 4.
Sea breeze is the air moving from __________ towards __________.
Answer:
Sea, Land
Try to Answer (Text Book Page No. 102):
What will you do during disaster.
(I will/I will not)
a. ______ watch TV when it rains heavily.
Answer:
I will not
b. ______ follow the warnings.
Answer:
I will
c. ______ stand under a tree when heavy wind blows.
Answer:
I will not
3rd Standard Science Guide Air Additional Questions and Answers
I. Choose the correct answer.
Question 1.
Very strong wind is called ___________.
(a) gale
(b) storm
(c) breeze
Answer:
(a) gale
Question 2.
Speed of wind is measured using an instrument called ___________.
(a) Thermometer
(b) Anemometer
(c) Barometer
Answer:
(b) Anemometer
Question 3.
Air is a ___________ resource, we cannot live without it.
(a) artificial
(b) natural
(c) renewable
Answer:
(b) natural
Question 4.
Plants breathe through ___________.
(a) leaves
(b) roots
(c) stem
Answer:
(a) leaves
Question 5.
We take oxygen and release ___________ gas while breathing.
(a) oxygen
(b) carbon dioxide
(c) nitrogen
Answer:
(b) carbon dioxide
II. Fill in the blanks.
Question 1.
A gentle wind is called ___________ (breeze / gale)
Answer:
breeze
Question 2.
Sea breeze takes place during ___________.(day time / night time)
Answer:
day time
Question 3.
___________ uproot trees and destroy the crops. (Breeze / Storm)
Answer:
Storm
Question 4.
___________ is generated from wind with the help of the wind mills. (Heat / Electricity)
Answer:
Electricity
III. True or False.
Question 1.
Air is required for burning.
Answer:
True
Question 2.
Air has no pressure.
Answer:
False
Question 3.
Air is colourless.
Answer:
True
Question 4.
We require polluted air for good health.
Answer:
False
IV. Match the following.
1. Speed of wind | a. Very strong wind |
2. Breeze | b. Anemometer |
3. Storm | c. Gentle wind |
4. Gale | d. Strong wind |
Answer:
1. Speed of wind | a. Anemometer |
2. Breeze | b. Gentle wind |
3. Storm | c. Strong wind |
4. Gale | d. Very strong wind |
V. Answer the following questions.
Question 1.
How is the wind measured?
Answer:
Speed of the wind is measured using an instrument called “Anemometer”.
Question 2.
How do fish breathe?
Answer:
Fish breathe through gills.
Question 3.
What ¡s inhalation?
Answer:
Inhalation is the process of taking the air inside.
Question 4.
What is exhalation?
Answer:
Exhalation is the process of releasing the air outside.
Question 5.
What happens to our chest when we breathe?
Answer:
When we breathe-in our chest raises up and when we breathe-out it lowers down.
VI. Answer in detail.
Question 1.
Prove with an experiment that air has weight.
Answer:
Take two balloons. Fill air in one balloon and keep the other balloon as it is. Take a stick and tie the balloons on the ends of the stick. The balloon with air comes down because air has weight.
Conclusion:
This experiment proves that air has weight.