# 6-4 Light

### Lesson List

Light travels at the speed of 186,000 miles per second!  In the time it takes you to blink your eyes, light travels around the earth seven times.

The material, through which light passes or travels, changes its speed.  Light travels through glass and water more slowly than it does through air.  Look at the diagram below.  Notice that the pencil appears to be broken in two.

This illusion occurs because the light is slowed down when it hits the water.  The light takes a different direction in the water than in the air.  This is called refraction.  Refraction is the bending of a ray of light as it passes from one medium into another.

Not only does light move very quickly and at different speeds through different materials, light is really a mixture of different colors of light.  Look at the diagram of the prism below.

When white light hits a prism at an angle the light bends.  The bending comes from the fact that the glass slows the light down.  Some parts of the light are bent more than others.  Violet bends the most and red the least.  The spread of colors created by the prism is called a spectrum.

 RED ORANGE YELLOW GREEN BLUE INDIGO VIOLET

Light travels at the speed of 186,000 miles per .

is the bending of a ray of light as it passes from one medium into another.

light is the mixture of the colors red, orange, yellow, green, blue, indigo, and violet.

A is a clear piece of glass or plastic that is shaped like a wedge.

Some parts of the light are bent more than others.  bends the most. bends the least.

The spread of colors created by a prism is called a .

Put the colors of the spectrum in order.  Start with the color that bends the most.