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The temperature coefficient of a material describes how much a certain property changes when the temperature increases or decreases by 1 Kelvin (equivalent to 1° Celsius). Some common properties that vary with temperature include electrical resistance and elasticity. Linear changes in a material’s properties make it straightforward to calculate a temperature coefficient, but the calculations become more difficult if the change in a property isn’t linear. There are a number of practical applications for materials that change with temperature, especially in electronics, which is why the study of temperature coefficients is important.
When a substance is heated or cooled, its properties can change. The resistance of an object, for example, can increase or decrease depending on its temperature. Other properties, such as the elasticity of a material, also can vary depending on temperature. Substances with properties related to temperature are useful for a variety of different applications, so scientists need to be able to accurately judge exactly what changes will occur to a particular type of material.
The temperature coefficient is a way for scientists to numerically describe the change in a material’s properties depending on the temperature. In other words, the temperature coefficient is how much a property changes when the temperature is changed by 1 Kelvin. The Kelvin scale is an alternative measure of temperature with a different starting point than the Celsius scale, but a change of 1 Kelvin is the equivalent of 1° Celsius.
How a material changes with temperature depends on a variety of factors. Some materials, for example, have a resistance to electricity that changes linearly with temperature. This means that, if the temperature doubles, then the resistance also doubles. It is much easier to calculate a temperature coefficient if the material varies linearly with temperature.
If the variation with temperature isn’t linear, then the temperature coefficient is more difficult to calculate. In this situation, scientists usually try to discover a variety of temperature coefficients that can be used in various temperature ranges. Even so, it’s not always possible to calculate a useful temperature coefficient.
An example of a practical application that’s possible because of a material’s known temperature coefficient is temperature-dependent resistors. These are used in a number of electric circuits and allow an engineer to change the way a circuit behaves depending on the external temperature. Without being able to predict how a material reacts to changes in temperature, this would not be possible.