Eli5 Why does metal give off light when heated?
In: Chemistry
Everything emits some kind of electromagnetic radiation based on its temperature. The hotter it is, the more energy it emits, and the higher the average frequency of the energy (this is known as black body radiation). Things at average temperatures on Earth’s surface emit energy that is mostly infrared (lower frequency than visible light). When things start to get up near 800-1000 degrees Celsius, the average frequency of the energy starts to enter the visible range, starting at red. As it gets hotter, it will get brighter and the average frequency shifts more toward yellow, then blue. The sun’s surface is around 5500-6000 degrees, and it’s that temperature that generates all that light. This type of energy emission is called incandescence, and it’s how incandescent light bulbs work. They pass a current through a filament causing it to get really hot (3000+ degrees) and so it emits light.
This isn’t just a feature of metals. However, many other materials will tend to under go chemical reactions destroying them before they get that hot.
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