Thermal Expansion and Contraction
Most of the matters, without some exceptions, expand with the increasing temperature. When you give heat to matters; speed of its particles increase and distance between them also increase which results in the increase of the volumes of matters. All expansions occurs in volume of the substance however, sometimes some of the dimensions of them expand more with respect to others. In this case we neglect the less expanded ones and assume expansion like linear expansion in long materials. Moreover, we take the expansion of plate as area expansion and finally we take the expansion in three dimensions as volume expansion. thermal expansion
Inverse of the expansion is called contraction, generally when matters lost heat and their temperatures decrease they contract. Now we will learn which factors effect expansion. If the initial volumes, areas or lengths of the matters are big enough their expansions with the same temperature are also big. In other words, expansion or contraction is linearly proportional to the initial volume of the matter. Different matters have different atomic structure, thus distances between the atoms are also different. They give different reactions to the same amount of temperature changes. So, another factor effecting expansion is type of matter. Final factor that affects expansion is the amount of change in temperature. Larger the change in temperature results in larger the change in the volume of matter. We get following formula from the explanations given above;
Where; ∆V is the change in the volume, α is the coefficient of thermal expansion and ∆T is the change in the temperature of the matter. α= Coefficient of thermal expansion is equal to the change in the volume of a unit of mass under 10C change in temperature. Expansion in Solid Matters
We will examine this subject under three title, linear expansion, area expansion and volume expansion. Linear Expansion: Picture given below...
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