Example 1
A 1.0 m steel bar with α = 12 × 10⁻6 K⁻1 heated by 100 K lengthens by about 1.2 mm.
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Physics tools › Linear thermal expansion
Mendeleev · Physics
Linear thermal expansion
A solid usually expands when its temperature rises. For modest temperature ranges, the change in length is approximately proportional to original length and temperature change.
Formula usedΔL = αL₀ΔT
Visual cue · thermal change
Calculate
Linear thermal expansion
What do the symbols mean?
ΔLchange in length
αlinear expansion coefficient
Llength
ΔTtemperature change
Two worked examples
Example 2
A 10 m rail with the same coefficient and ΔT = 40 K changes length by about 4.8 mm.
Good to knowThe coefficient α depends on the material and varies somewhat with temperature. The formula is a linear approximation.