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.
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:
- A light source containing green light shines on it.
- The reflected green light reaches an observer - such as your eyes or a camera.
At any other time, a green leaf is not green.
Try it out for yourself. Go outside in the daytime and find a green leaf. Then take that green leaf into a dark room and shine a red LED light bulb on it. You will not see the leaf as green. What color do you think the leaf will be?
This story was outlined using Columns, the Cornell Notes App
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