system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 why/how fire produces light?
gpt
Everything with a temperature above absolute zero radiates energy in the form of electromagnetic radiation. The higher the temperature, the more it radiates, and higher the average frequency of that radiation. 

At standard Earth temperatures, things mostly radiate at frequencies lower than we can see, but if things get hot enough they can start to radiate visible light frequencies. 

Fire is a reaction that produces lots of heat, so it raises the temperature of stuff around it to the point where it can radiate visible light.