When an object is heated it increases in size.
Increase in size on heating is known as Expansion .
- Fixing the iron blade of the soil digging tool with a wooden handle.
- The iron blades of these tools have a ring in which the wooden handle is fixed.
- These rings are slightly smaller in size than the wooden handle.
- To fix the handle with the ring, the ring is heated.
- When heated,the ring becomes slightly larger in size(Expands).
- Now the handle fits easily with the ring.
- When the ring cools down it contracts and fixes tightly with the handle.
- Fixing a metal rim to a wooden wheel.
- Again in this the metal rim is made slightly large r than the wooden wheel
- To fix the metal rim to a wooden wheel.
- We need to heat the metal rim .
- On heating the metal rim increases in size.
- And fixes easily to the wooden wheel.
- On cooling , the metal rim fixes tightly on the wooden wheel.
- When the object is cooled , it decreases in its size
- Decrease in size on cooling is known as Contraction.
Evaporation of Water
- When water is boiled ,it changes into steam(water vapor)
- If we cool the steam it forms water again .
- Thus,this process of boiling of water is a reversible change.