Basic Science and Technology – Primary 6 Weekly Short Class Lesson Notes for Second Term

WEEK 2 – AIR AND AIR PRESSURE

INTRODUCTION TO AIR

Air is a mixture of gases that surrounds the Earth.

We cannot see air, but we can feel it when it moves as wind.

Air is very important because all living things need it to breathe.

 

MEANING OF AIR PRESSURE

Air pressure is the force that air exerts (pushes) on everything around us.

Even though air is light and invisible, it has weight and can press on objects.

For example, when you pump air into a balloon, the balloon expands because of air pressure inside it.

 

IMPORTANCE OF AIR PRESSURE

1. It helps us to breathe – Air pressure helps air to move in and out of our lungs when we breathe.

2. It helps birds and airplanes to fly – Differences in air pressure help birds and airplanes lift and stay in the air.

3. It helps in weather formation – Air pressure affects weather conditions like rain, wind, and storms.

4. It is used in drinking with a straw – When we suck a straw, air pressure pushes the drink into our mouth.

5. It helps in pumping tyres and balls – Air pressure keeps tyres, footballs, and balloons firm and in shape.

6. It helps wind to blow – Wind is formed when air moves from high-pressure areas to low-pressure areas.

It is used in spraying liquids – Air pressure is used in sprays like perfume and insecticide.

 

DEMONSTRATING IMPORTANCE OF AIR PRESSURE WITH SIMPLE OBJECTS

1. Balloon and Bottle Experiment

Materials – An empty plastic bottle and a balloon

Steps:

• Put the balloon inside the bottle and stretch its mouth over the bottle opening.

• Try to blow the balloon.

Observation – The balloon does not inflate easily.

Explanation – Air inside the bottle pushes back. This shows that air has pressure.

 

2. Cup and Paper Experiment

Materials – A plastic cup and a small piece of paper.

Steps:

• Put the paper inside the cup.

• Turn the cup upside down.

• Try to shake the paper out.

Observation – The paper stays inside the cup.

Explanation – Air pressure pushes the paper upward and holds it in the cup.

 

3. Drinking Straw Experiment

Materials – A cup of water and a straw

Steps

• Put the straw in the water.

• Suck the straw.

Observation – Water moves up the straw.

Explanation – Lower air pressure inside the straw allows higher air pressure outside to push the water up.

 

4. Balloon and Pin (Optional Teacher Demonstration)

Materials – A balloon and a pin

Steps:

• Inflate the balloon.

• Gently prick it with the pin.

Observation – The balloon bursts.

Explanation – The air pressure inside the balloon is released suddenly.

 

5. Syringe Experiment (Without Needle)

Materials – A plastic syringe (no needle)

Steps:

• Pull the plunger.

• Push it back while blocking the opening.

Observation – The plunger is hard to push.

Explanation – Air trapped inside resists because of air pressure.

 

10 MULTIPLE CHOICE QUESTIONS AND ANSWERS ON AIR PRESSURE

INSTRUCTION – Choose the correct answer from the options A – D. 

1. Air pressure is the ______. 

A. colour of air

B. force of air pushing on objects

C. sound made by air

D. weight of water

 

2. Which of the following shows air pressure?

A. Stone sinking in water

B. Paper tearing

C. Ice melting

D. Balloon bursting when overfilled

 

3. Air pressure helps us to ______.

A. eat food

B. sleep

C. breathe

D. read

 

4. When we suck a straw, water rises because of ______.

A. gravity

B. heat

C. air pressure

D. light

 

5. Which object is kept firm by air pressure?

A. Football

B. Book

C. Spoon

D. Plate

 

6. Wind is formed when air moves from ______. 

A. cold to hot areas

B. high pressure to low pressure areas

C. low pressure to high pressure areas

D. sea to land only

 

7. Air pressure is useful in which of these? 

A. Writing

B. Flying of aeroplanes

C. Sleeping

D. Cooking

 

8. Air pressure is strongest at ______. 

A. the top of a mountain

B. high altitude

C. sea level

D. outer space

 

9. Which material is best to show air pressure in a classroom experiment?

A. Balloon

B. Stone

C. Chalk

D. Eraser

 

10. Air pressure can be described as air ______. 

A. smell

B. taste

C. colour

D. push

 

FILL IN THE GAP QUESTIONS

11. Air is a mixture of ______ that surrounds the Earth.

12. Air pressure is the ______ exerted by air on objects.

13. Air pressure helps us to ______ properly.

14. Wind is formed when air moves from ______ pressure to low pressure.

15. Tyres and balloons remain firm because of ______.

 

SHORT ANSWER QUESTIONS

16. What is air?

17. Define air pressure.

18. Mention one importance of air pressure.

19. How does air pressure help when drinking with a straw?

20. Give one example that shows air has pressure.

 

ANSWER KEYS 

1. B 2. D 3. C 4. C 5. A 6. B 7. B 8. C 9. A 10. D 11. gases 12. force 13. breathe 14. high 15. air pressure

16. Air is a mixture of gases that surrounds the Earth.

17. Air pressure is the force with which air pushes on objects.

18. Air pressure helps us to breathe.

19. Air pressure pushes the liquid up the straw into the mouth.

20. A balloon inflates when air is blown into it.