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Expansion of solids

When a material gets hot it expands - this is because the molecules in it are moving about more vigorously and so need more room.
As a solid is heated the molecules vibrate more violently and the solid expands in all directions. We will just look at the increase in length. The hotter it gets and the longer it was to start with the more the solid expands.

Different materials expand by different amounts for the same rise in temperature.
The amount of expansion depends on:
(a) what material it is
(b) how big the temperature rise is
(c) how long it was to start with
© Keith Gibbs 2009