Dark colors absorb more heat because they absorb more electromagnetic radiation, including visible light and ultraviolet (UV) radiation. Electromagnetic radiation is a form of energy that travels through space at the speed of light and can be absorbed by matter.

The absorption of electromagnetic radiation by matter is determined by the material’s atomic and molecular structure and the frequency of the radiation. Materials that have a large number of atoms or molecules per unit volume, such as metals, tend to absorb more electromagnetic radiation than materials with a low density, such as air.

The color of a material is determined by the wavelengths of visible light that it reflects. Dark colors, such as black, absorb more electromagnetic radiation across all wavelengths, including visible light and UV radiation, because they have a higher density of atoms or molecules per unit volume. This is why dark colors tend to absorb more heat than light colors.

In contrast, light colors, such as white, reflect more electromagnetic radiation, including visible light and UV radiation, because they have a lower density of atoms or molecules per unit volume. This is why light colors tend to reflect more heat and stay cooler than dark colors.

The ability of a material to absorb or reflect electromagnetic radiation, including heat, is known as its thermal emissivity. Materials with a high thermal emissivity, such as dark colors, tend to absorb more heat, while materials with a low thermal emissivity, such as light colors, tend to reflect more heat.

In conclusion, dark colors absorb more heat because they absorb more electromagnetic radiation, including visible light and UV radiation. The absorption of electromagnetic radiation by matter is determined by the material’s atomic and molecular structure and the frequency of the radiation. Dark colors, such as black, have a higher density of atoms or molecules per unit volume and tend to absorb more electromagnetic radiation across all wavelengths, including visible light and UV radiation. This is why dark colors tend to absorb more heat than light colors.