Question

Describe an activity that air expands on heating.​

Answer 1

Answer:

When the bottle is placed in hot water, the balloon expands. When the bottle is placed in cold water, it contracts. Inference: This happens because when the bottle is placed in hot water, the air in it becomes warm and expands due to which balloon also expands.

Answer 2

$\huge{\bf{\green{\fcolorbox{yellow}{black}{\underline{\color{yellow}{Question}}}}}}$

Describe an activity that air expands on heating.

$\huge{\bf{\green{\fcolorbox{yellow}{black}{\underline{\color{yellow}{Answer}}}}}}$

Introduction —

• Air expands on heating. Why does this happen?

➡ It is because the particles of air on becoming warm, move away from each other and take up more space. So we can say that air on becoming hot occupies more space. Since the particles move away from each other, the air becomes less dense and lighter in weight.

As a result, warm air rises up. On the contrary, on cooling the particles of air come closer to each other. Due to this, the volume of air becomes less, the air becomes more dense and heavier. This can be demonstrated by a simple activity.

Activity I

• Materials Required: balloons, trough, ice cold water, hot water, bottle.

• Method: Take a bottle. Tie the balloon tightly on the neck of the bottle. Place the bottle in a container having hot water. Record your observation. Now place the bottle in cold water. Again observe.

• Observation: When the bottle is placed in hot water, the balloon expands. When the bottle is placed in cold water, it contracts.

• Inference: This happens because when the bottle is placed in hot water, the air in it becomes warm and expands due to which balloon also expands. When the bottle is placed in cold water, the air in the bottle contracts due to which balloon also contracts.

Daily life examples where you can see the air expands on heating —

• Hot air ballon rises up: This is because the air in the balloon expands on heating. It also becomes lighter hence rises up.

• Monsoon Winds: Monsoon winds are caused due to more heating of land at the equator during summer months. Due to this, the air above the land at equator rises up. The moisture-laden winds from oceans towards southern hemisphere blow towards the equator. These are the monsoon winds which cause rainfall.

• Land Breeze and Sea Breeze: They are caused due to uneven heating of the air. The land always gets heated and gets cooled faster as compared to water. In coastal areas, during the daytime, the air above the land gets heated very quickly as compared to water in the sea. The air above the land is hotter and lighter rises up. The cool air above the sea rushes towards land to take its place. This causes sea breeze. During night land gets cooled faster whereas sea is still hot. The air above the sea being comparatively hotter rises up. The air above the land rushes towards the sea. This causes the land breeze.

Explanation:

$\huge \fbox \red {Hope \: it \: helps \: you}$