how does thermal expansion and thermal equilibrium help us measure Temperature?

Question

samgrace · Answer

All elements behave differently, and have different properties that are constant, for example boiling point, melting point, conductors/insulators. Most elements expand when heat is applied, such as metal or gas (thermodynamics).

An example of the thermometer is a cylinder with mercury inside (its room temperature state is liquid.... oh and it's a metal) with some red dye. Then when the base of the cylinder is put into heat, the mercury expands up into the higher areas of the cylinder, as a rate proportional to the heat transfer, therefore a scale can be put on it's side.

The same can be done for gas with a slightly trickier set up.


Temperature formulae for centigrade and Fahrenheit exist too!