Thermal Expansion Coefficient

         

Thermal Expansion Coefficient Formula
\( \alpha =  l_f - l_i \;/\; l_i \; ( T_f - T_i ) \)     (Thermal Expansion Coefficient) \( l_f = \alpha \; l_i \; ( T_f  -  T_i ) + l_i   \) \( l_i =  l_f \;/\; \alpha \; \left( T_f - T_i  \right) + 1    \) \( T_f = ( l_f - l_i \;/\; \alpha \; l_i )  + T_i  \) \( T_i = ( l_f - l_i \;/\; \alpha \; l_i )  - T_f  \)
Symbol	English	Metric
\( \alpha \)  (Greek symbol alpha) = Thermal Expansion Coefficient	\(in \;/\; in\;F\)	\(mm \;/\; mm\;C\)
\( l_f \) = Final Length	\(in\)	\(mm\)
\( l_i \) = Initial Length	\(in\)	\(mm\)
\( T_f \) = Final Temperature	\(F\)	\(C\)
\( T_i \) = Initial Temperature	\(F\)	\(C\)

Thermal expansion coefficient, abbreviated as \(\alpha\) (Greek symbol alpha), also called coefficient of thermal expansion, and linear thermal expansion coefficient, is the percentage change in the length of the material per degree of temperature change, heated solid or liquid.  It is a material property that quantifies how much a material expands or contracts when its temperature changes.  When a material is heated, its particles gain kinetic energy and move more vigorously, causing them to spread out and increase the material's overall volume.  Similarly, when a material is cooled, its particles lose kinetic energy and become less active, leading to a decrease in volume.

The thermal expansion coefficient is defined as the fractional change in size (length, area, or volume) of a material per unit change in temperature.

Different materials have different thermal expansion coefficients, meaning they will expand or contract by varying amounts for the same change in temperature.  For example, metals generally have higher thermal expansion coefficients compared to ceramics.  This property is essential to consider in various engineering applications, such as when designing structures that experience temperature variations to ensure that they can withstand the resulting dimensional changes without causing issues or failures.

• See Articles  -  Thermal Expansion Coefficient of a Material