Why do dark colors absorb heat?
Dark colors become hotter in sun light than light colors for a reason that dark colors absorb more light. A blue shirt appears blue when the sunlight falls on it and when the blue light energy gets reflected. The reflection of blue light will impart blue color to the shirt as it reaches our eyes. Light colors will reflect more light. Dark color will absorb more light. The light absorbed by the dark clothes will get converted into heat.
Dark colored clothes appear dark as they reflect very less light. Light colored clothes appear bright as they reflect the light more. The light that is not reflected by the dark colored clothes will be more absorbed into the material. So, people are not suggested to wear black in summer because the clothes will get hotter.
Dark colored objects are found to get heated rapidly in strong light as the objects will absorb much of the radiation in the visible wavelengths. The dark objects will turn this energy into heat. The dark colored objects get heated rapidly and also become cool rapidly. This is because the dark colored objects are known to radiate heat when the light stops falling on them.
The dark colored objects are black in color as they absorb totally the electromagnetic radiation. The object that absorbs the entire radiation will convert that energy into thermal energy. While light colors will reflect the electromagnetic radiation completely that makes them to look white. As the object do not absorb anything from the light, it need not convert the light into thermal energy.
As every object appears in a color which is reflected back from them, dark colored objects in order to appear black should not reflect any light. Hence, they absorb total light and change them into heat energy.