system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is fire hot?
gpt
This is a good question because it actually shows an example where we look at things "the wrong way": 

It is not hot because there is fire. There is "fire" because it is hot.

What do we call "fire": If you make things hot, anything really, it starts to glow from a deep red over a brighter red to a bright orange to a bright blue.

If you look at your cooking plate and you make it hot, that is what you see. There is no light because you have a built-in lamp, but because the plate gets hot like a piece of iron in a fire. If you have a welding torch it gets so hot you start to see the blue colour. 

Now if you have a chemical reaction, for example the carbon in wood bonding with the oxygen from the air, it might get so hot that the gasses around and the ash-particles start to be so hot that they begin to glow red and orange. That effect is what we call fire.