THERMAL EXPENSION CLASS 12 PHYSICS CLASS NOTES

Thermal expansion is the tendency of materials to change their dimensions in response to a change in temperature. When a substance is heated, its particles gain energy and move more vigorously, causing an increase in the distance between them. This leads to an expansion in the material's volume, length, or area, depending on its state (solid, liquid, or gas). Thermal expansion is characterized by the coefficient of thermal expansion, which quantifies how much a material expands per degree of temperature change. This phenomenon has practical implications in engineering and everyday life, requiring allowances in structures like bridges, railways, and pipelines to prevent damage caused by temperature fluctuations. Conversely, cooling causes contraction, reversing the process.