Density tells you how much mass is packed into a given volume. It is calculated with the equation density = mass ÷ volume, or ρ = m ÷ V. Density is in kilograms per cubic metre (kg/m3) when mass is in kilograms (kg) and volume is in cubic metres (m3).
The equation can be rearranged. To find mass, multiply density by volume: m = ρ × V. To find volume, divide mass by density: V = m ÷ ρ.
Example 1: an object has a mass of 2.0 kg and a volume of 0.00025 m3. Its density is 2.0 ÷ 0.00025 = 8000 kg/m3.
Example 2: water has a density of 1000 kg/m3, so 3 m3 of water has a mass of 3000 kg. Example 3: 600 kg of a liquid with a density of 1200 kg/m3 has a volume of 600 ÷ 1200 = 0.5 m3.