Thermal expansion

Definition

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.

5 Must Know Facts For Your Next Test

1. Thermal expansion can be quantified using the coefficient of thermal expansion, which varies for different materials.
2. Linear expansion is relevant for one-dimensional objects like rods and wires, while volumetric expansion applies to three-dimensional objects.
3. 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.
4. 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.
5. 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.

Volumetric Expansion:

The change in volume of an object due to temperature change.