A Kids Guide to Light

Light is always around us, but we don't usually spend a lot of time thinking about it. Nevertheless, light is an extremely important part of our daily lives. Without light, we couldn't see anything in our world, including colors. There would be no light bulbs, no fires, and no stars in the sky. Without light, a lot of the things we do every day would no longer be possible. However, many of us don't understand how light works or what it is made of. Below, you will find answers to all these different questions, as well as a multitude of resources to help you learn more about light. 

What is Light?

Light is a specific type of energy that travels in a straight line and is made up of electro-magnetic radiation. Unlike most other forms of energy, light can be detected by the human eye. Light can move very fast. In fact, it travels at about 300,000 kilometers per second in open air. Nothing else in the world, including other forms of energy, can travel as fast as light can. Our main source of light on earth is the sun. However, light also comes from other sources, such as fires and light bulbs. Regardless of its source, light always travels at the same speed in open spaces.

Colors of Light

Though natural light appears to be white in color, there are actually several different colors that make up light. The primary colors of light are red, green and blue, and each color is composed of a different wavelength. Mixing the primary colors in different ways can create all other colors. When all of the colors are combined, the result is white light. Of the primary colors, the longest wavelength belongs to red, the second longest wavelength belongs to green, and the shortest belongs to blue. However, while the longest light wavelength of all is red, the shortest wavelength of all belongs to violet.

The color of objects in our universe is actually composed of the colors of light that the object reflects. For example, an object that appears to be blue reflects blue light and absorbs all of the other colors. Likewise, an object that appears to be red to the human eye, such as an apple, reflects red light and absorbs all of the other colors.

Reflection and Refraction

Reflection occurs when light waves come into contact with an object that has a smooth, shiny surface and bounce back from the object. For example, light reflects off of a mirror. Refraction, on the other hand, occurs when light passes through one transparent substance and into another and bends. An example of refraction is the bending of light that occurs when it passes from air into water.

Sunlight often passes through drops of water in the atmosphere. When this occurs, the light may refract into the water, reflect off the inner surface, and then refract as it moves back out of the drop. When the first refraction occurs, the light is separated into the colors that compose it. During the second refraction, the separation is intensified. When this series of events is complete, a rainbow is the result.

Light and Optics: A collection of videos about light and optics that are appropriate for children.

The Light Stuff: An interactive activity that demonstrates the speed of light to children.

Color Our World: A page with information about how colors are formed.

Primary Additive Colors: An interactive tutorial that shows kids how the primary colors mix to make new hues.

About Rainbows: A page with in-depth information about rainbows and how they are created.

Lights, Prisms, and the Rainbow Connection: An activity that shows children how a rainbow is formed.

Rainbows: An article describing how a rainbow is formed.