Linear Thermal Expansion
The fractional change in length of a solid material per degree change in temperature.
Governing formula
ΔL = α L0 ΔT
SI unit
K⁻¹ (°C⁻¹)
In depth
Caused by asymmetric interatomic potential wells: higher thermal energy causes atoms to vibrate with larger amplitudes around wider average separations.
Examples in the real world
Expansion gaps placed between steel railway tracks to prevent rail buckling during hot summer months.