Question

to prove that air exerts pressure​

Answer 1

Answer:

There are various examples that can prove that air exerts pressure, and few of them are:  

Water glass trick: fill a glass with one third water and place a cardboard to cover up the entire mouth of the bottle or glass.

Then shake the bottle few times and leave the cardboard.

The air pressure will hold the cardboard for at least 15 seconds automatically.  

Similarly, you can experiment with fountain bottle and fill the bottle with half full water and use straw to hold the air pressure into it.

Even you can also find the air pressure extract automatically in ping pong ball and kissing balloons.  

Answer 2

Aim:

Aim: To prove that air exerts pressure.

Materials required:

glass tumbler, water, cardboard

Procedure:

1. Fill the glass tumbler with water up to its brim, such that there are no air bubbles inside it.

2. Keep a rectangular piece of cardboard on the mouth of the tumbler.

3. Giving the cardboard support with one hand, invert the tumbler.

4. Slowly remove your hand.

5. Note your observations.

6. Now, fill one-fourth of the tumbler with water and the remaining three-fourths with air.

7. Again, place the cardboard on the mouth of the tumbler. Invert the tumbler.

8. Note your observations.

Observations:

In the first case, you observe that the cardboard is stuck to the tumbler even when you remove your hand. This happened because the air pressure was acting upwards on the paper and the cardboard did not fall as shown in the picture. However, in the second case, the pressure of air inside the tumbler acted downwards and pushed the cardboard out and the water started running.