Density is the amount of mass in a volume. The more dense a substance is, the heavier it is for the same amount of volume.

The formula for density is:

density = `frac(text(mass))(text(volume))`

Density is measured in g/cm3 or kg/m3.


1. A cuboid of lead, 3cm by 5cm by 2cm, has density of 11.34 g/cm3. What mass is the cuboid?

Answer: 340.2g

Volume = 3 x 5 x 2 = 30cm3.

Rearrange the formula to density x volume = mass

30 x 11.34 = 340.2g

2. The density of water is 1000 kg/m3. A swimming pool has been constructed on the top of a building. The swimming pool is 1.5m deep throughout, and is 10m by 15m. What mass of water will be contained within the pool?

Answer: 225 tonnes

The volume of the pool is 1.5 x 10 x 15 = 225m3.

Rearrange the equation to density x volume = mass

225 x 1000 = 225000Kg, os 225 tonnes.