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Chapter 11. Light is an Electromagnetic Wave

If you want to look at the questions now, you can click here.

This reading is about the relationship between electromagnetic waves, light and color.

Shocking Fact: Your eye can see around seven million different colors.

Electromagnetic waves create one of the most important forms of energy for a human’s survival, light! You might be wondering, what does light have to do with electricity? Or even color? Read on to learn more about light. Electromagnetic waves create one of the most important forms of energy for human survival, light!  Light is actually an electromagnetic wave. This wave is made out of a photon. A tiny particle that moves through space. This means that light is a form of energy. If you have ever felt the sunlight on a summer day, you already know that energy from light can make heat! 

A Burning Flame: Light is made of moving electric and magnetic fields. Light also moves in waves. Therefore, light is an electromagnetic wave.

So, now that we have a basic understanding of how electricity is related to light…Have you ever thought about how your favorite colors are created? What makes a color blue? Or yellow? When we look at an object, we are really seeing reflected light. When we see a grumpy cat, the photons of light are reflected off the grumpy cat and into our eyes. When waves of light hit an object, some waves are absorbed by the object and some are reflected. 

The reflected waves are what you see.  Different wavelengths of reflected light create different colors! For example, when you see your favorite red shirt, the shirt is absorbing all the colors of light except for the color red. The frequency of light that we see as red is being reflected, and we see that shirt as red. 

Beauty in the Sky: A rainbow’s colors are always ordered in the same way: Red, Orange, Yellow, Green, Blue, Indigo, and Violet! You can remember this by the letters: ROYGBIV (you can say it like a name, Roy G. Biv).

The only colors that are different are white and black. White is a combination of all colors, so when we see white, the object is reflecting all the colors of light the same. Black is the opposite. When we see a black object that means almost all the colors of light are being absorbed. When you look at a black poster, the poster is absorbing all types of light. And, when you wear white shorts, they are reflecting all the light waves (but still get grass stains!).