DENSITY

Density is the measure of how close and how heavy are the particles of matter in an
object. It is measured in kg/m3 or g/cm3 or g/mL.

Rule for Density
Density (ρ) =

Mass
Volume
Example of Density Rule
Q. A stone has a mass of 10 grams. When it is immersed in a measuring cylinder of
water, the water level rises 5 millilitres. What is the density of the stone?
Density =

Densities of Some Common Substances
SUBSTANCE
Air
Feathers
Petrol
Water
Aluminium
Lead

Mass
10 grams
=
= 2 g/mL
Volume
5 mL
DENSITY
(g/mL)
0.002
0.045
0.7
1
2.7
11.3
Floating and Sinking
The density of water is 1 g/mL. Any substance (such as ice, petrol or oil) whose density
is less than 1 will float. Any substance (such as lead) whose density is more than 1 will
sink.