why is it easier to heat things up, than it is to cool them down?

Question

why is it easier to heat things up, than it is to cool them down?

In: 143

Answer 1

To heat something up, you just have to generate thermal energy. There are multiple ways to do this, but the easiest are chemical (burn something) or electrical (run electricity through a resistor).

You can’t ‘generate’ cold, so the only way to make something colder is to expose it to something that’s a lower temperature. This is limited by the speed of thermal transfer – heat can only move from hot to cold at a limited rate. You can speed this up by increasing the temperature difference, but ‘cold’ only goes down to 0K or -273C so you can’t gain much there.

In practical terms though, you can dunk something into liquid nitrogen and get it cold pretty fast so this isn’t a major problem.