What Is Thermal Expansion?

Thermal expansion ^[1] usually refers to the case of constant external pressure. When the temperature increases, the volume of most substances increases and the volume decreases when the temperature decreases. Thermal expansion is related to physical properties such as temperature, heat capacity, binding energy, and melting point. The main factors affecting the expansion performance of materials are the effects of phase transition, material composition and structure, and anisotropy. The measurement methods of thermal expansion mainly include optical method, electrical measurement method and mechanical method. The entry also gives the bulk expansion coefficient of common liquids and the linear expansion coefficients of various metals at the end.

What happens to an object due to a change in temperature

Thermal expansion nature of solid materials ^[3]

When the pressure remains the same, due to the change in temperature,

Measurement temperature conditions: 20 ° C, unit: 1 / ° C (1 / K)

Mercury (mercury) 0.00018

Water 0.000208

Glycerol (Glycerin) 0.00050

Concentrated sulfuric acid

Ethylene glycol 0.00057

Aniline

Xylene 0.00085

Gasoline 0.00095

Turpentine 0.00100

Kerosene 0.00100

Toluene 0.00108

Ethanol (alcohol) 0.00109

Acetic acid

Bromine 0.00110

N-octane 0.00114

Trichloroethylene 0.00117

Methanol 0.00118

Carbon disulfide

Carbon tetrachloride

N-heptane 0.00124

Benzene 0.00125

Chloroform 0.00127

Ethyl acetate 0.00138

Acetone 0.00143

Diethyl ether

Measurement temperature conditions and units: 20 ° C, 10 ^ -6K ^ -1

Metal name element symbol linear thermal expansion coefficient

Beryllium Be 12.3

Al 23.2

Antimony Sb 10.5

Lead Pb 29.3

Copper Cu 17.5

Cadmium Cd 41.0

Cr 6.2

Iron Fe 12.2

Germanium Ge 6.0

Gold Au 14.2

Iridium Ir 6.5

Mg 26.0

Manganese Mn 23.0

Mo 5.2

Nickel Ni13.0

Platinum Pt9.0