Why Do Different Colors Absorb Different Amounts Of Heat Energy?

The answer to this question may come from a simple conversation about whether to wear light-colored clothing or dark-colored clothing during an outdoor adventure. Nearly everyone has learned that lighter colors and white reflect the heat of the summer sun, rather than absorbing it as black and darker colors do.

abservheat-energy-1There may be two parts to this investigation, one involving the color itself and the other involving the reflection or retention of heat. In general, an object that is seen as one consistent color is reflecting that one color back to the viewer and absorbing all the others. This is a rather simple explanation of a complex scientific fact. White, for example, doesn’t “play well with others” at all. White reflects everything in the color spectrum.

Colors are determined by such terms as “waves” and “frequency.” Some have more energy because they have higher wave density. What can happen is that certain colors may hold more heat because of this fact. If we could measure tiny, tiny differences in temperature we would find that we will naturally be warmer in certain colors than in others.

When we decide to wear a lighter color outdoors, in the sun, it is because most of the heat and energy is being reflected away from us and our bodies. Wearing dark colors then would mean the clothing would absorb energy and heat, keeping us warmer than we need to be in the summer, for example. In cooler weather, it may be best to have darker colors. Some elementary science experiments have shown that objects that are closed on all sides but one will retain different levels of warmth/heat depending on the color the inside of the object is painted. If we use a range of colors for this experiment, the box that is white or light yellow inside will absorb less of the light or sunshine while the black or dark red interior will be warmer (it absorbs more energy).

There is another term that we should introduce here: radiation. A dark-colored object will absorb all the frequencies mentioned earlier – waves radiate at different levels, thus the term “radiation.” Of course, this will vary somewhat depending on what the object is composed of. Some materials, such as steel, naturally get hotter or colder at different rates than other materials. But when two identical surfaces are painted or otherwise covered with different colors, the temperature difference will be noticeable.

So, when you are deciding on what to wear, consider how much sun you will encounter and what the air temperature is. Darker colors will absorb the energy and some of that will be transferred to the body, keeping you warmer. The cooler temperature of the body will attempt to “steal” some heat/energy from the warmer clothing. This is good information to have when thinking about painting a house or choosing a roofing material for a house. Color and heat retention are based on which frequencies are absorbed and which are reflected. It’s as simple, and as complex, as that.

Category: Energy, Science

One Comment on “Why Do Different Colors Absorb Different Amounts Of Heat Energy?”

Linda Garb wrote:

Would a charcoal gray roof add significantly more heat to a house than a medium brown roof?

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