Question

What is thermal expansion? Given an example of thermal expansion of solids?

Answer 1

1. When a substance is heated, the molecules absorb heat energy and start vibrating faster.
2. They move farther apart from each other leading to the expansion of the substances, the solids expand less compared to liquids and liquid expands less compared to gases.
3. This phenomenon of expansion of solids, liquids, and gases upon heating is called thermal expansion.

Thermal expansion of solids:

1. Solids expand upon heating and contract on cooling.
2. Solids are held together by a strong intermolecular force.
3. So expansion in solids is not much and is sometimes not very prominent.

Example: Power lines and telephone lines are usually connected between poles in a way that they hang a bit loose, this is to prevent the wires from snapping as they contract during winter and expand during summer.