What is Thermal expansion and contraction ?

In physics, thermal expansion is the tendency of matter to increase in volume or pressure when heated. For liquids and solids the amount of expansion will normally vary depending on the material's coefficient of thermal expansion. While for gases the change in volume or pressure is related to the container that the gas is in, this can be easily estimated by the ideal gas law. When things expand tensile forces are created. When things contract compressive forces are created. To accurately calculate thermal expansion of a substance a more advanced Equation of state must be used. This equation would be able to calculate thermal expansion among with many other state functions.

In physics, thermal expansion is the tendency of matter to increase in volume or pressure when heated. For liquids and solids the amount of expansion will normally vary depending on the material's coefficient of thermal expansion. While for gases the change in volume or pressure is related to the container that the gas is in, this can be easily estimated by the ideal gas law. When things expand tensile forces are created. When things contract compressive forces are created.

Thermal expansion and contraction in the dictionary means a rising current of warm air (used)'s an act of incresing and the process of becoming smaller. (technical phase)