The standard units of density (SI) is the kilogram per cubic metre (kg/m3). Other density units for GCSE are the gram per cubic centimetre (g/cm3). To convert from g/cm3 to kg/m3, you multiply by 1000 or 103.
Working out the massEdit
Use a balance. With a gas or liquid, measure the beaker or flask with either just air in (liquid), or with a vacuum in (gas). Then measure mass with gas or liquid in the beaker/flask. Take the second reading from the first to find the mass.
Working out the volumeEdit
Measure the dimensions and thus work out the volume.
Use a displacement can: Fill it up so it over-flows, when all the water possible has drained out, put the solid in the displacement can, and measure the volume of the water that comes out of the can using a measuring cyclinder.
Liquids or gasesEdit
Use a flask or a measuring cylider.
Floating or sinkingEdit
If an object has a higher density than the fluid it is in, it sinks. If it has a lower density, it floats. For example, glass (d = 2.5g/cm3) sinks in water (d = 1g/cm3), but floats in mercury (d = 13.6g/cm3)