1. Light Energy
Science
January 2013

2. What is light?
Light: A Visible Form of Energy
Light is a form of energy. Like all kinds of energy, it can be transformed from other forms of energy. Think about the lights you use every day. Light energy doesn’t travel through the wires into a lamp. Electrical energy travels through wires into a lamp. Once the electrical energy gets to a lamp, it is changed into light energy.

3. How can light be described?
Light can be described as an electromagnetic wave. The light you see is only one type of electromagnetic wave. Other types include radio waves, microwaves, infrared light, ultraviolet light, X rays, and gamma rays.
The electromagnetic spectrum

4. How Does Light Travel?
Light travels in waves. They move very fast. Even though the sun is very far away, light energy from the sun takes just a few minutes to get to Earth. The electromagnetic waves can travel through empty space. This is different than sound waves, that can only travel through matter- like air or water. Sound waves cannot travel through the empty places in space, but light can still travel through it.
The Nature of Light

5. Transparent, Translucent, and Opaque

6. Let’s Review!
Light is a form of energy that travels in electromagnetic waves.
Light waves have amplitudes, frequencies, and wavelengths. When light is a different color, or when a light is bright or dim, the frequency and amplitude have changed.
Light travels in a straight line from its source. Light can travel through a vacuum, like space, and through translucent solids, liquids, and gases.
Light travels faster than anything else in the universe. No matter what the light source, light and heat are given off.

7. Refraction

8. What is Refraction?
Light can travel through transparent materials such as air, glass, or water. When light travels in these materials, it travels in a straight line. However, if light passes from one transparent material into another transparent material, the light will change direction. This is called refraction. Refraction happens because the speed of light is different in different materials.
Refraction: The Bending of Light

9. Reflection

10. What is Reflection?
What do you already know about reflection? Think about using a mirror!

11. What happens when light hits a surface?
When light hits a surface, reflection happens. When light waves hit an object, some of the energy is absorbed. Some of the energy may go through the object. Some of the energy is reflected from the objects surface. Light waves behave like a basketball hitting a smooth gym floor. The basketball will bounce off of it. That is reflection.
Does light only bounce off of smooth objects, such as a mirror?