Effect of Temperature on Bodies:

This is a common observation & experience that the size of a body increases as the temperature increases while it decreases as the temperature decreases. Thus, temperature rise results in expansion that means enhance in linear dimensions of the body, and temperature fall results in contraction, that means. Decrease in the linear dimensions of the body. The magnitude of alter brought in linear dimensions of the body by temperature is described through an intrinsic property of the material, of which the body is build of, called coefficient of linear thermal expansions or contraction.

The coefficient of linear thermal expansion or contraction of a material is described as the change in length per unit length per degree change in temperature of the body which is build of the material. The values of this coefficient, α of some common engineering materials are listed in below Table.

From the definition, α might be written as,

α =  (ΔL/ L) × (1/ ΔT)

where, ΔL is the change in length over a entire length L while the temperature is changed by ΔT. Therefore,

                         ΔL = α × L × ΔT

Table