Define the term density of a substance.

State the S.I. and C.G.S. units of density. How are they related?

Arrange the following substances in order of their increasing density:

1. iron
2. cork
3. brass
4. water
5. mercury

How does the density of water change when:

(a) it is heated from 0°C to 4°C,

(b) it is heated from 4°C to 10°C ?