|Why does black attracts heat and white reflects heat?|
|Question Date: 2018-03-07|
Objects that absorb light appear dark to us
while objects that reflect light (and therefore
heat) appear light (white) to us.
(Quick note: Light and heat are two
different forms of the thing we call energy ).
Things that emit brighter light and more heat
have higher energy.) Things that look
lighter/whiter reflect many or all colors of
light, and these emitted colors (colors given off
by the object) come together to make these things
look white. Black objects look black because
they absorb all colors of light, and then
give off the energy from the light in the form
of heat. It is because of how well objects
absorb or reflect light and heat that they appear
either darker or lighter to us, not that they
absorb heat because they're black. The colors
are just representations of how well things retain
There are several ways that heat can be
transmitted, but in this case we're talking about
light, so it's helpful to talk about
radiative heat, which is transmitted
through infrared radiation that is invisible to
our eye. In general, the color of something
might not be as significant as the general
material of an object. (For example, is it
metal, is it plastic, and is it wood?)
However, you could do a simple experiment with
black and white paper. On average when compared
to black paper, white paper reflects more light,
so it absorbs less energy from visible and
near-visible light. Because white paper absorbs
less energy, it may not get as hot.
Light is a type of energy. So is heat. Light that
you see is light that is going into your eyes,
which means that it is light that is not going
into whatever you are seeing. White is a brighter
color than black, so that means that something
that is white is reflecting the light that you see
when you see that it is white. That means
that it is reflecting more energy, and gaining
This is a really fun question because it
touches on the difference between the two
different places that color can come from.
Color can come from light and it can also come
from pigments. Light can come in any single
color, in a mixture of all colors. When all colors
of light combine, they make white light.
Most lightbulbs produce white light which is why
they appear white when we look at them. When there
is no light, everything looks dark or black so we
can call black the absence of light.
All of this changes when we talk about
pigments. Pigments are dyes that we can use to
make physical things look colorful. They can
be found in our clothes, paints, and even our
skin. Pigments reflect certain colors of light
which makes its way into our eyes so we can see
the color, and it absorbs others. When a
pigment absorbs a color of light, it does not
reach our eyes so we cannot see that color.
Take a green book for example: it would absorb all
colors of light besides green. That green light
bounces off the green book, the green light makes
its way into our eyes and we see the book as
Getting back to your question,how come black
things absorb heat and white things reflect
heat. We know that white objects have white
pigments in them, meaning that they reflect white
light. Since white is the combination of all
light, that means that white things reflect all
light and absorb none. Black objects do the
opposite. We see them as black because they
absorb all colors of light and reflect none.
Thank you for your question!
Click Here to return to the search form.
Copyright © 2020 The Regents of the University of California,
All Rights Reserved.