LIGHTS, LIGHTS, LIGHTS YEAH!

Life on earth would be impossible without light. Plants use energy from the sun to grow and make food for all living things.

Light is a form of energy which travels in small, invisible waves.

Light moves faster than anything else in the universe. It can travel more than 186,000 miles per second. That means light can circle the earth eight times in one second!

But light does not travel through all substances at the same speed. Like you, light moves more quickly through air than it does through water. When light slows down, it bends. This is called refraction.

When light shines on a surface, some of the rays bounce back off. This is called reflection. Flat shiny surfaces, like glass, work the best for reflection. Have you ever seen light reflecting off a lake on a calm day?

Although we usually think of light as colorless, it does appear in color. We can see the colors when light rays are separated as they pass through certain substances like water and glass. Light appears in seven distinct colors known as a spectrum.

There are two other kinds of light rays which are not visible to the human eye. One is called ultraviolet, which is the light that causes you to tan or burn in the sun. The other one is infrared, and it is the light that warms you when you sit in the sun.

Experiment with this concept!

Make your own rainbow!!

Isaac Newton, an English physicist, was the first to realize that white light is actually made up of the colors of the rainbow. He discovered this by using a prism, which is a triangular piece of glass that can separate light rays. When light goes through a prism, it slows down and bends a little. The rays of light move at different speeds so when they hit the prism, they are bent to different angles.

MATERIALS:

• a sunny day
• rectangular tub or baking dish
• mirror
• piece of white paper

WHAT TO DO:

• Fill the tub about halfway with water, and place it by a window in the sun.
• Place the mirror inside the tub resting against one side. Position the mirror so that the sun light is shining directly on it.
• Put the white paper in front of the mirror and move it around until the rainbow colors appear on the paper.

HOW IT WORKS:

The water acts as a prism and separates the light rays. When the rays hit the water, they slow down and refract (bend) to different angles and the colors become visible. If you have a camera you can take a picture of your own rainbow!

WHAT DO YOU THINK?

Can you think of other ways we see bent light? How about fun house mirrors? what happens when you catch sunlight through a magnifying glass? How about reflections from your watch face or eye glasses?