Thermal expansion is the increase in volume of a substance due to an increase in temperature. This occurs because particles move more and take up more space as they absorb heat.
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Thermal expansion can be quantified using the coefficient of thermal expansion, which varies for different materials.
Linear expansion is relevant for one-dimensional objects like rods and wires, while volumetric expansion applies to three-dimensional objects.
The formula for linear expansion is $\Delta L = \alpha L_0 \Delta T$, where $\alpha$ is the coefficient of linear expansion, $L_0$ is the original length, and $\Delta T$ is the change in temperature.
For volumetric expansion, the formula is $\Delta V = \beta V_0 \Delta T$, where $\beta$ is the coefficient of volumetric expansion and typically $\beta = 3\alpha$ for isotropic materials.
Different states of matter (solid, liquid, gas) exhibit different levels of thermal expansion; gases generally expand more than liquids and solids.
Review Questions
What happens to the volume of a substance when its temperature increases?
How do you calculate linear thermal expansion?
Why do gases typically exhibit more thermal expansion compared to solids?
Related terms
Coefficient of Thermal Expansion: A material-specific constant that quantifies how much a material expands per degree change in temperature.
Linear Expansion: The change in length of an object due to temperature change.