Ask A Scientist
Why does black take in heat?
Asked by: Imisioluwa Ademoyo
School: St. James Middle School
Teacher: Mr. Martinkovic
Hobbies/Interests: Drawing, playing piano, reading about jobs, and making stories.
Career Interest: Doctor, Scientist, Medical Lawyer, Engineer and a professor.
Answer from Alexsa Silva
Director of Instructional Laboratories
Research area: Education, photochemistry, organometallics.
Ph.D. School: Federal University of Rio de Janeiro, Brazil
Post Doctoral Studies: Binghamton University
Interests/hobbies: Music and travel
We know from experience that what we call the color “black” takes in or, more correctly, absorbs heat better than any other color. In order to understand why this is so, we have to understand what color is, how you see all the different colors around us and how to relate color with heat. The colors that we see from various objects are due to the object reflecting light that our eyes can detect. Light is made up of photons, which we can call packets of energy, and these photons travel together as waves. A light wave can be transmitted, reflected or absorbed. The color that we see, or do not see, is related to what happens when the light interacts with the object. Let's consider the white light that can come from the sun or from a lamp in your house. The white light is a combination of several different colors, different light waves with different wavelengths. When this light goes through a transparent object, like a clear window, the glass transmits most of the light. But, when the same light reaches a red rose, the rose petals reflect the red light and all the other colors are absorbed by the petals. When the same white light shines on a white tablecloth, nearly all the light is reflected, while very little is absorbed. On the other hand, when the white light reaches the black coat hanging on a chair, most of the light is absorbed by the coat, so the black color that we see is in fact due to the lack of color being reflected. Almost all the light is absorbed. Since light is a form of energy, the black coat absorbs the energy from the white light. Have you noticed how we tend to wear white or very light colored clothes in the summer? That’s because we do not want our clothes to absorb heat! All the energy absorbed by an object will eventually be released. This energy will be released as a slightly different wave and have a longer wavelength. We cannot see it as a color, it is outside our eyes ability to detect it, but we can detect it as heat. All the other colored objects release energy as heat, but because black objects absorb most of the light shining on them, we notice that more heat is released from black objects than from any other color.