What is thermal expansion ?

Explanation

(i) When heat energy is supplied to a body, there can be an increase in the dimension of the object. This change in the dimension due to rise in temperature is called thermal expansion of the object.
(ii) The expansion of liquids ( eg, mercury) can be seen when a thermometer is placed in warm water.
(iii) All forms of matter (solid, liquid , and gas) undergo expansion on heating.
(iv) When a solid is heated, the atoms gain energy and vibrate more vigorously , results in the expansion of the solid.
(v) The different types of expansion of solid are
1. Linear expansion
2. Superficial expansion
3. Cubical expansion
Expansion liquids and gases:
(i) When heated, the atoms in a liquid or gas gain energy and are forced further apart.
(ii) The extent of expansion varies from substance to substance.
(iii) For a given rise in temeprature, a liquid will have more expansion than a solid and a gaseous substance has the highest expansion when compared with the other two.