Across

1. a material that lets some light through

3. light travels through and bends

5. a material that does not let light through

6. a material that lets let through

Down

2. light stops

3. light bounces

4. light travels through

Rainbows are beautiful, and we can see them after a storm. Kids see rainbows and get excited. Adults get excited, too. Kids may point at them, and adults stare at them. Poets feel inspired and write about them. In other words, everyone feels hope when they see a rainbow.

Scientists get excited when they see a rainbow, too. To them, a rainbow tells something about the characteristics of light: refraction and reflection.

Rainbows are made of some simple, common ingredients. These are sunlight and water droplets. A rainbow will form only if these ingredients are arranged correctly. Water droplets are nearly perfect spheres. Sunlight must hit the water droplet at a proper angle. When this happens, light passes into the droplet. There, it changes speed and bends or refracts.

Refraction makes the light separate into colors. The colors always separate in the same way. The order does not change. This order is red, orange, yellow, green, blue, indigo, and violet. Violet, or purple, is always on the inside curve of a primary rainbow. When we see light, it looks white. However, light is made up of all the colors of the rainbow. We can see these colors when refraction takes place.

Sunlight hits the water droplet, bends, and then reaches the back of the droplet. The back of a water droplet is like a mirror. This part of the droplet reflects the colors of the rainbow. Sunlight that is refracted inside the water droplet is reflected off the back of the droplet to us. That is how we can see colors of a rainbow.

Two rainbows in the sky are a rare sight. That is something special. The inner arch is the primary rainbow, and it is brighter. The secondary rainbow is on the outer side. It is a mirror image of the primary rainbow. The colors of this rainbow are flipped or reversed. Also, the second rainbow is dimmer than the primary rainbow.

A moonbow is a rare variation of a rainbow. It is also known as a lunar rainbow. Moonbows take place at night. They have the same colors as an ordinary rainbow. It is very difficult for us to see, or perceive, these colors in dim light. This is why they appear white to the naked eye. With the use of a special camera, you can see the colors in a photograph.

You can see the properties of a rainbow in your own yard. Turn on the water and make a fine spray through a hose. Make sure the sun is behind you. Sunlight will reflect off the back of the water droplets. You will be able to see a rainbow just like the larger version.

We all enjoy rainbows, and we can learn a great deal about light from rainbows. When refraction and reflection happen in the sky, it makes a sight more splendid than what an artist can create with a paintbrush.