# Density

## What is Density?

Density?

Density is a physical characteristic of every substance.

It is defined as "Mass per unit volume". Density is calculated as Mass/Volume and is measured in g/cm(3).

What is Mass?

Mass is a measure of the quantity of matter. Mass is often confused with weight.
The mass of anything is constant but weight is effected by location. A person will weigh less on the moon or in space than on earth because of the difference in gravity. Mass (the amount of matter - blood, bones) etc does not change. Weight changes because Weight = Mass x Gravity.

What is Volume?
Volume is the amount of space an object occupies.

Density = Mass/Volume
Density is calculated by dividing Mass by Volume.
Units for Mass are grams (g)
Units for Volume are cm cubed or cm (3)* Volume of a liquid may be measured in
Litres (l)
Units for Density are g/cm(3)

Examples of use of Density:
To identify whether water is mixed with milk
To measure the amount of liquid in an object
To measure the amount of water in whiskey in case it has been given more water!
To identify substances
To measure the purity of substances
Used by engineers

Density and Flotation

Background material on density