What do you think of when you think of light?  The sun shining in the sky?  A flashlight in the night?  A warm fire?  The glow of a TV?  These are what we call visible light or light that you can see.  But visible light is only a small part of what light is made of.  Before we learn about the other parts, let's talk about what light is.

Everything looks a little bit brighter in the sunlight.

Light moves like a wave moves through the ocean, only it moves through the air and sky around you.  Light waves can move through clear things like a window or a glass of water. This is one of light's properties, which is a fancy way of saying this is one of the things it can do.  Let's look at some more of light's properties.

Light moves fast.  Let's say you could ride a wave of light like a train.  How far do you think you could go in one second?  Go ahead.  Think about it.  One second is not a very long time.  Do you think you could make it to the park down the street?  Farther?  How about from California to New York?  Farther?  From your house to Australia?  Farther!  In one second, your wave of light will move around the whole Earth seven times.

Let's watch a light wave move from the sun to Earth.  It shoots through space like a golden bullet.  The sun is so far away, it takes eight whole minutes for that wave of light to reach our planet.  Watch as it gets here and hits matter "" a fancy word for the stuff that makes up everything.

Once light hits something, like a wall, it bounces off of it like a ball.  Now the light wave moves in a different direction and not so fast because it just hit something.  Watch as the light wave goes right ...into your eye.  That may sound like it hurts, but this is how you see!  Your eye catches some of the light waves that bounce off the things around you and makes a picture for your brain.  That's why when the lights are off, the sun is down, and the fire is out, you won't see anything.

Even light hits a brick wall and bounces back.

Now let's talk about some of the properties of light that are invisible or what you can't see.  The invisible parts of light are also helpful.  They help plants grow and warm the earth.  We use them to listen to the radio, tan our skin, and even cook our food!

What do you think about now when you think of light?  There are many more things to learn about light: like how it makes colors, how your eye turns the light it catches into shapes, and how you can play with light.  Even light is a mystery that scientists had to solve.