Thermal Expansion Calculator

Thermal expansion is the tendency of matter to increase in volume when heated. For solids, linear expansion (change in length) is calculated using ΔL = αL₀ΔT, where α is the coefficient of linear expansion. Most materials expand when heated and contract when cooled.

The coefficient of linear expansion (α) is a material property that describes how much a material expands per degree of temperature change. It's measured in 1/°C or 1/K. For example, aluminum has α = 23×10⁻⁶ /°C, meaning a 1-meter aluminum bar expands by 23 micrometers for each °C increase.

Bridges expand and contract with temperature changes. Without expansion joints, thermal stress could crack or buckle the structure. Expansion joints allow the bridge to safely expand in hot weather and contract in cold weather. A 100-meter steel bridge can expand over 7 cm between winter and summer!

While most materials expand when heated, a few rare materials (like water between 0-4°C and some ceramics) actually contract when heated. These materials have negative thermal expansion coefficients. This unusual property is used in specialized applications like telescope mirrors that must maintain precise shapes.

Thermal expansion is critical in precision instruments and machinery. Temperature changes can cause misalignment, gaps, or interference. Engineers account for this using materials with low expansion coefficients (like Invar steel), temperature compensation systems, or maintaining constant temperatures in labs and factories.

Linear expansion applies to one dimension (length). Area expansion affects two dimensions (β ≈ 2α). Volume expansion affects three dimensions (γ ≈ 3α). This calculator focuses on linear expansion, which is most relevant for rods, beams, and structural elements where length change is the primary concern.