It does. If you are using that rod to measure something else, or calibrate another rod, you are supposed to keep it at a given fixed temperature. Also, the sta

It does. If you are using that rod to measure something else, or calibrate another rod, you are supposed to keep it at a given fixed temperature. Also, the standard of length was changed quite a while ago to one based on the definition of the second, and the speed of light. Edit: here are the latest standards https://en.wikipedia.org/wiki/2019_redefinition_of_the_SI_base_units https://en.wikipedia.org/wiki/2019_redefinition_of_the_SI_ba...