Thermal Expansion Calculator
Calculate how much a material expands or contracts when temperature changes.
🌡️ Science📐 ΔL = α × L₀ × ΔT
Original length (m)
Temperature change (°C)
Material
Please enter valid values.
Formula & Reference
| Variable | Formula | Units |
|---|---|---|
| Thermal Expansion Calculator | ΔL = α × L₀ × ΔT | millimeters |
Step-by-Step Examples
Example 1
Steel Bridge 100m
100m steel bridge, +50°C summer.
- ΔL = 12e-6 × 100 × 50 = 0.06 m = 60 mm
- Why bridges need expansion joints!
✓ 60 mm expansion
Example 2
Aluminum vs Steel
1m each, +100°C.
- Al: 23e-6 × 1 × 100 = 2.3 mm
- Steel: 12e-6 × 1 × 100 = 1.2 mm
✓ Al: 2.3mm vs Steel: 1.2mm
Example 3
Invar Precision
100m Invar bar, +50°C.
- ΔL = 1.2e-6 × 100 × 50 = 6 mm
- vs steel: 60 mm — 10x less!
✓ 6 mm (vs 60mm for steel)
Real-World Applications
Civil Engineers
Account for thermal expansion in bridges and buildings.
Materials Engineers
Select materials by expansion coefficient.
Physics Students
Calculate linear expansion.
HVAC Engineers
Account for pipe expansion in thermal systems.
Common Mistakes to Avoid
⚠️
No expansion joints
Steel bridges without expansion joints buckle in summer heat. 100m of steel needs ~60mm of expansion room.
⚠️
Confusing linear and volumetric
Linear α for 1D. Volumetric β ≈ 3α for volume changes.
Frequently Asked Questions
Why do power lines sag in summer? ▾
Steel and copper expand with heat. Lines are strung with intentional sag to accommodate this.
What is Invar? ▾
Fe-Ni alloy with extremely low α (~1.2×10⁻⁶/°C vs steel's 12). Used in precision instruments.
Bimetallic strip thermometers? ▾
Two metals with different α bonded together. Temperature change causes bending proportional to ΔT.