NIOS Class 10 Science Activity 14.2 Thermal Energy

In this activity, we will learn about the expansion of gases when heated. We know that gases do not have a definite shape or volume. You can go through activity 14.1 to learn about the expansion of liquids.

NIOS Class 10 Science and Technology (212) Project File

This activity is based on the NIOS Class 10 Science and Technology (212) Chapter 14: Thermal Energy, Module 4.

Demonstration of Expansion in Gases

Aim

To observe the expansion of gases on heating and compare with solids and liquids

Materials Required

   1.  Glass tube

   2. Mercury 

   3. Burner

   4. Marker

   5. Hard surface

Procedure

We take a thin-walled glass tube with a narrow neck and trap a small drop of mercury inside it. Now we heat one end of the tube and immediately press it against a hard surface to seal it.

After some time, the tube cools down to normal temperature, we hold it and mark the initial position of the mercury drop.

In this way, we have a column of air trapped between the sealed end and the mercury drop.

 Now we heat the tube and observe the movement of mercury in the tube.

Observation

The mercury drop shifts downwards in the tube on warming slightly.

Explanation

When air(gas) is heated, its particles gain kinetic energy and move faster. This increases pressure and forces the mercury to shift its position.

 Gas particles are loosely packed and have a weak force between them, so with a small temperature rise, these particles move and expand.

Conclusion

 We can conclude that gases expand very fast on a small rise in temperature as compared to solids and liquids.

Frequently Asked Questions

   1. Why is mercury used in this activity?

Answer – Mercury acts as a visible indicator and shows movement caused by air.

   2. What is the aim of the activity?

Answer – To find the expansion of gases on heating.

   3. Write some uses in daily life of the expansion of gases.

Answer – The Principle of expansion of gases is used in hot air balloons, thermometers, and barometers.

Related Topics

1. Activity 14.1