Coefficient of Expansion
| Formula / Notation | α = (1/L)(dL/dT); β = (1/V)(dV/dT) ≈ 3α |
|---|---|
| Also Known As | Thermal expansion coefficient, coefficient of thermal expansion (CTE), α (linear), β (volumetric) |
What is Coefficient of Expansion?
The coefficient of thermal expansion is a measure of how much a material expands per degree of temperature increase. For gases, the volume coefficient of expansion at constant pressure is approximately 1/273 per degree Celsius (Gay-Lussac's law). Liquids and solids have smaller but important coefficients that must be considered in engineering applications.
Formula & Notation
Other Names / Synonyms: Thermal expansion coefficient, coefficient of thermal expansion (CTE), α (linear), β (volumetric)
Properties & Characteristics
Uses & Applications
Safety Information
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
Key Facts
Frequently Asked Questions
The coefficient of thermal expansion is a measure of how much a material expands per degree of temperature increase. For gases, the volume coefficient of expansion at constant pressure is approximately 1/273 per degree Celsius (Gay-Lussac's law). Liquids and solids have smaller but important coefficients that must be considered in engineering applications.
Expansion coefficients are critical in engineering design: bimetallic strips in thermostats, expansion joints in bridges and railways, glass-to-metal seals, precision optical instruments, and thermometer design. Materials with low α (Invar alloy, fused silica) are used where dimensional stability is…
Differential thermal expansion between components can cause mechanical stress and failure. Thermometers and sealed liquid systems must be rated for the temperature range expected. Borosilicate glass (Pyrex) has a low α, making it more resistant to thermal shock than soda-lime glass.
The formula or notation for Coefficient of Expansion is: α = (1/L)(dL/dT); β = (1/V)(dV/dT) ≈ 3α