Air

When you blow air through a tight mouth, the air will be significantly colder. Why?

Air we blow out is cold if the air outside is warmer than our breath.

Observe these figures. Put a ( $⩗$) mark where air occupies space.

The weight of air acting on a surface causes _____.

Air expands on ____.

Air expands when heated.

What is the use of air in windmills? 

Give any three uses of air.

On the basis of the evaluation of three glasses fill in the table below.

How will you know that there is air in an empty vessel?

Select the appropriate term from the box for the picture given below.

(Air has weight, Air fills up space, Air is used for burning, Air contains smoke, dust and germs, Air is used to fill tyres)

Select the appropriate term from the box for the picture given below. 

(Air has weight, Air fills up space, Air is used for burning, Air contains smoke, dust and germs, Air is used to fill tyres)

Air does not occupy space.

Air takes the shape of the container.

Bring a tumbler up to your mouth. Suck air out of the tumbler. See what happens. Why does it get stuck to your mouth?

Give a scientific reason why air has no shape of its own.

State two uses of siphon.

Give scientific reason:

Air is a mixture of gases, but to us, it appears to be a single gas. 

How do you feel the air around you?

Give an experiment to show how air pressure helps to push down or lift the liquid up in the straw.