# Density

When looking at density, it is important to first understand the states of matter. The three common states of matter are solidsliquids and gases.

## Understanding Density

The density of an object is its mass for a given volume. For example, let’s compare two blocks with the same volume.

• The high-density block has a lot of mass packed into its volume
• The low-density block has a lower mass packed into the same volume

## Calculating Density

To calculate the density of an object, we need:

• The mass of the object
• The volume of the object

The mass of the object can be measured using a balance and a measuring cylinder can be used to measure the volume of a liquid. To measure the volume of a solid, measure its side.

The equation to calculate density is:

• ρ = Density in grams per centimetre cubed (g/cm3)
• M = Mass in grams (g)
• V = Volume in centimetres cubed (cm3)

## Example

A rock has a mass of 15 kg and a volume of 1 m3. Calculate the density.

Looking back at the equation:

Density (g/cm3) = Mass (g) ÷ Volume (cm3)

We know 15 kg = 15000 g and 1 m3 = 100 cm3

So. density = 15000 g ÷ 100 cm3 = 150 g/cm3

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