system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: When looking at a flame, what exactly is the orange part? How does flame work?
gpt
Everyday combustion, like burning a candle, involves carbon and other chemicals in the combustible material reacting with oxygen in the air. This reaction is exothermic, meaning that it gives off thermal energy, or heat. Given enough heat, electrons in the atoms off the gas start to become excited, ie they reach a higher energy level. This arrangement is unstable, and the electrons will collapse back to their previous energy level, and in doing so they will release their excess energy as electromagnetic radiation. The wavelength of this radiation is determined by what you're burning and how much energy the combustion released, but for everyday materials like wood and candlewax, the wavelengths will be long enough to produce visible yellow, orange and red light as well as infrared light, which you can feel as heat when you get close to the flame.