Thermal Expansion

Thermal expansion of a liquid or solid is the change in dimensions of an object due to a change in temperature.  This includes linear thermal expansion (solids), area thermal expansion (solids), or volumetric thermal expansion (liquids & solids).  If the thermal expansion of a gas is to be determined, the Ideal Gas Law is used.

Linear Thermal Expansion - The change in length of an object depends on the material used, the original length of the object, and the change in temperature of the object.

Δ L  =  α L₀  Δ T

Δ L → change in length of the object

α → coefficient of linear thermal expansion (Table 12.1 in your book)

L₀ → the original length of the object

Δ T → change in temperature of the object

Area Thermal Expansion - The change in area of an object depends on the material used, the original area of the object, and the change in temperature of the object.

Δ A  =   2 α A₀  Δ T

Δ A → change in area of the object

α → coefficient of linear thermal expansion (Table 12.1 in your book)

A₀ → the original area of the object

Δ T → change in temperature of the object

Volumetric Thermal Expansion - The change in volume of an object depends on the material used, the original volume of the object, and the change in temperature of the object.

Δ V  =  β V₀  Δ T

Δ V → change in volume of the object

β → coefficient of volumetric thermal expansion (Table 12.1 in your book).  You might notice that β is approximately equal to  3 α.

V₀ → the original volume of the object

Δ T → change in temperature of the object