Process

• When light hits an object, the atoms of the object begin to absorb the energy of the light. This slowly energizes the atoms, allowing the atoms to move faster. As the atoms move faster on an atomic level, the whole object begins to emit heat as a response to the light. This allows the surface of the object to feel warm to touch.
  
  

Wavelengths

• Light, as a form of energy, works in wavelengths. Wavelengths signify the type of light, such as ultraviolet or infrared light. Light human beings can see with their eyes is simply called visible light. Each light has a different wavelength level, and as a result the color a human can see reflects this wavelength. For example, purple has a low wavelength while red has a higher wavelength. The higher the wavelength, the more energy in the light. Hence, infrared light is hotter than ultraviolet light.
  
  

Absorption

• The colors a human sees come from an object's ability to absorb all wavelengths and their colors. The color an object has is the wavelength it reflects. For example, an apple appears red to the human eye because the apple's atoms absorb all other wavelengths except red. Hence, objects receive their color then from what light they do not absorb. This plays a key role in heat. For example, although red light has a higher wavelength and has more energy or heat, red objects are not hot. This is because the object absorbs lower wavelengths except red.
  
  

Heat and Absorption

• Depending on what wavelengths are absorbed, the heat accumulated from light will increase. For example, if an object is purple, the lowest wavelength, that means the object is absorbing all other wavelengths in the light spectrum. This means, more light and thus energy is being absorbed by the object. Hence, the darker an object, which means the lower wavelength it has, the hotter and more absorptive the object becomes. Colors like black, purple or blue, and other darker colors are the best colors to absorb heat. While objects that are red, yellow or orange require more energy or light to be hot.