I know red = hot, but what about heating metal causes it to glow the color red?
In: Physics
The color is actually the temperature,. Think of the rainbow: red, orange, yellow, green, blue, indigo, violet.
When any material heats up and it reaches about 1000 K it starts to emmit light. First visible color is red (least energy). Keep on heating the material and it will get orange, then yellow and eventually white.
White is a mix of all colour, i.e. all temperature. Any material heated to about 1500K will emmit white light since different atoms have different temperature and what we see is the mixture of all these temperatures emitting light at different wave lengths.
It’s called black body radiation, the atoms in the metal get energy from the heat, and then release it as light, this light can vary from all the way in the infrared at room temperature, to warm white at ~3000°, and even blue at tens of thousands of degrees.
It’s not just metal, it’s everything, literally any
material, but metals are the most common things to get to those temperatureS
[Black body radiation.](https://en.wikipedia.org/wiki/Black-body_radiation) It’s not only metal, but all matter.
Basiscally everything emits light, which wavelength depends on the temperature. Hotter things will emit photons of smaller wavelength, and colder things will emit photons of bigger wavelengh. Red is the largest wavelength our eyes can see, so objects start by glowing red when they get hot (then go white if they get really hot)
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