Why Objects have Colors - Illustration - Animation

Lawrence Weru
Lawrence Weru

Why do objects in nature have the colors that they do?

Although sunlight appears white, it contains all the colors of the rainbow. Objects absorb some of those colors and reflect others into your eyes. Different objects reflect different colors. The colors that are reflected into your eyes are considered the colors of the objects.

COMPOSITION OF LIGHT

White light is composed of multiple different colors of light. When multiple colors of light come together, you get white light.

When you see white light, you're seeing multiple different colors of light overlapping.

The simplest way to get white light is to mix together equal amounts of red, green, and blue light. But it's not the only way. The Sun's light is a white light that contains all the colors of the rainbow, not just red, green, and blue. We call this rainbow of colors a color spectrum. Different sources of light can have a different spectrum. When you walk outside in the daytime, every color that you see in nature is a color that was inside of the Sun's white light.

WHY THE WORLD IS SO COLORFUL

Why is an apple red? Why is a leaf green? A light source can have a rainbow of colors inside of it. The sun is a light source. When white light from the Sun reaches an object's surface, some of the colors in the light get absorbed, and others get reflected. The color that you see is the reflected light.

An apple is red because when white light reaches the apple, the apple absorbs all of the colors of the rainbow that exist in that white light, except for red. The red light, which isn't absorbed by the apple, is reflected into your eyes. And so you see the apple as red.

Green leaves are green for the same reason. When white light reaches the leaf, the leaf absorbs all of the colors of the rainbow that exist in that white light, except for green. The green light, which isn't absorbed by the leaf, is reflected into your eyes. And so you see the leaf as green.

COLOR IS AN EVENT

If a tree falls in a forest and no one is around to see it, are its leaves green?

The fact that a "green leaf" is only green because it reflects green light into our eyes leads us to an interesting conclusion: color is an event.

A green leaf is only green when:

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Lawrence Weru

Larry's contributions are featured by TEDx, Fast Company, and Gizmodo Japan, and cited in books by Routledge and No Starch Press. His stories and opinions are in magazines and newspapers including Slate, Vox, Toronto Star, Orlando Sentinel, and Vancouver Sun. He is a Harvard Medical School Dean's Scholarship awardee, a Florida State University "Notable Nole," and has served as an invited speaker at Harvard, FSU, and USF. He illustrates the sciences for a more just and sustainable world.