Thermal Linear Expansion

Thermal expansion is the tendency of matter to change in volume in response to a change in temperature. All materials have this tendency.  For this course we will concentrate on the expansion in one direction.

When a substance is heated, its particles begin moving and become active thus maintaining a greater average separation.  The degree of expansion divided by the change in temperature is called the material's coefficient of thermal expansion.  These coefficients, like most coefficients, are specific to each material

Things to keep in mind

1. When dealing linear expansion, we primarily concerned with solids (gases and liquids take the shape of their container)

2. As the temperature increases the kinetic energy of the particles increase.

3. The bonds between particles in a solid is rigid

4. Solids express its kinetic energy as vibrational energy (back and forth motion)

5. As the vibrational energy increases it pushes adjacent particles further away (hence the expansion).

Important Equation

lo   =  Original length

=  Temperature

l    =  length

=  Coefficient of thermal expansion