Question

Describe an experiment to prove that solids expand on heating.

Answer 1

$Method$:

The apparatus consists of a metal ball which fits exactly through a ring attached to a stand when both are at room temperature.

Heat the ball using a Bunsen Burner for a few minutes and then try to pass it through the ring.

$Observations$:

The ball does not pass through the ring when it is hot.

leave the ball on the ring and allow it to cool for some time. The ball will now pass through the ring

$Conclusions$:

This proves that solids expand on heating and contract on cooling.

Why do solids and liquids expand when heated?

Objects expand when heated because the heat 'gives' molecules more energy, so they move around more. This vibration, as molecules are pushed further apart, is manifested as a larger volume.. An exception is water, which contracts as it cools until you reach about 3.98 ° C then starts to expand as it cools more. This is caused by the shape of water molecules.. Then again, there is Zirconium Tungstate which contracts as it is heated up to 800 o C (an effect caused by lattice formation that twists and turns individual molecules).