NIOS Class 10 Science Activity 26.2 Solution - Air and Water Explained

This activity demonstrates that air exerts pressure on surrounding objects.

Air and Water Activity Solution

This activity is based on the NIOS Class 10 science and technology (212) Chapter 26- Air and Water Module 6- Natural Resources.

Aim

 To show that air exerts pressure

Materials Required

   1. Empty mineral water bottle

   2. Hot water

   3. Cold water

Procedure

We take an empty plastic water bottle and pour some hot water into it. After that, we tightly screw the bottle’s cap to make it airtight.

Now we pour cold water over the outside surface of the bottle and observe what happens.

Observation

The bottle shrinks and collapses inward after pouring cold water on it.

Explanation

When we take hot water in the empty bottle, the air inside becomes hot and expands.

When cold water is poured on the airtight bottle, the air inside cools and contracts.

So, a partial vacuum is created inside the bottle, and the air pressure inside becomes less than the atmospheric pressure outside. That’s why the atmospheric pressure acts from outside and presses the bottle inward and causing it to collapse.

Conclusion

This activity explains that air exerts pressure.

Frequently Asked Questions

   1. Why does the air inside the bottle contract on cooling?

Answer -  The water molecules come closer on decreasing the temperature so the volume is reduced.

   2. What causes the bottle to collapse in this activity?

Answer – The atmospheric pressure outside the bottle is greater than the pressure inside after cooling, so the bottle collapses.

   3. What does this activity prove?

Answer – This activity proves that air exerts pressure in all directions.