How is it possible that certain colours absorb heat and others reflect it? They are just ‘colours’?
Why if you are wearing black pants, you get warm, but with white, less so – even if it’s the same material?
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It’s not that some reflect and some absorb.
All materials are on an albedo scale, from 0 to 1.
At 0, an object will absorb all light, and reflect nothing. This would be completely black. It would also radiate heat very well; if warm and not being heated up by an external source, it would quickly radiate that heat.
At 1, exact opposite. It will reflect all light, and absorb nothing. It would look like a perfect mirror. It would not radiate heat. If hot, and not heated by an external source, it would remain hot.
In terms of clothes, this has implications. On a sunny day, not exorcising much, the primary source of heat is the sun, so wearing black makes you very hot. Wearing white, with a higher albedo, you reflect the sunlight more and stay cooler. But at night, if you are exorcising, it flips. Now the primary source of heat if your body, so wearing black will help you stay cool, and if you want to keep warm, you should wear something as reflective as possible; hence why emergency blankets look like tinfoil.
(This is also why radiators should be black, like the one in your car, but interior designers around the world all failed thermodynamics, so enjoy your higher heating bill and wasted energy)
Colour is just the wavelength of reflected light. A black object is reflecting very little, a blue object is reflecting light in the blue wavelength very well, but absorbing reds more, a white object reflects most colours pretty well, and a mirror reflects everything. In that sense, your question is backwards; colour is just reflecting radiation (heat).
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