The formula for expansion of solids

You can put the results for solid expansion in a formula as:



The linear expansivity is a constant for a material and is how much a unit length of the material would expand for a 1^o rise in temperature — it is a very small number: 0.000 0012 for iron.
This means that a 1 m length of iron would expand by 0.000 0012 m when its temperature is raised by 1^o C.