We could repeat the
experiment of weighing any iron ball and carry out the same operation
of dividing its mass by its volume and we would always get the same
value.
This value , which is density in the case
of iron is 8.7 g/cm3, and does not depend on the piece of
iron we use.
Density can be expressed in any unit of mass divided by any unit of
volume. So the density of iron in SI units is 8,700 kg/m3,
and that of liquid water is 1000 kg/m3
.
Lead has a density of 11,300
kg/m3, gold 19,300 kg/m3 and platinum 21,400 kg/m3.
As you can see platinum is 21.4 times denser than water: 1 m3
of water has a mass of 1,000 kg and 1 m3 of platinum has a
mass of 21,400 kg.
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