15 Facts About Thermal expansion

Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions.

The relative expansion divided by the change in temperature is called the material's coefficient of linear thermal expansion and generally varies with temperature.

Coefficient of thermal expansion describes how the size of an object changes with a change in temperature.

Volumetric thermal expansion coefficient is the most basic thermal expansion coefficient, and the most relevant for fluids.

For isotropic materials, the area and volumetric thermal expansion coefficient are, respectively, approximately twice and three times larger than the linear thermal expansion coefficient.

When calculating thermal expansion it is necessary to consider whether the body is free to expand or is constrained.

Common engineering solids usually have coefficients of thermal expansion that do not vary significantly over the range of temperatures where they are designed to be used, so where extremely high accuracy is not required, practical calculations can be based on a constant, average, value of the coefficient of expansion.

Linear Thermal expansion means change in one dimension as opposed to change in volume .

Above example assumes that the Thermal expansion coefficient did not change as the temperature changed and the increase in volume is small compared to the original volume.

The absolute Thermal expansion can be measured by a variety of techniques, including ultrasonic methods.

Control of thermal expansion in brittle materials is a key concern for a wide range of reasons.

Good example of products whose thermal expansion is the key to their success are CorningWare and the spark plug.

In most cases there are complex issues involved in controlling body and glaze expansion, so that adjusting for thermal expansion must be done with an eye to other properties that will be affected, and generally trade-offs are necessary.

For liquids usually the coefficient of volumetric Thermal expansion is listed and linear Thermal expansion is calculated here for comparison.

Common materials like many metals and compounds, the thermal expansion coefficient is inversely proportional to the melting point.