How to Make a Rainbow

Learn how to make a rainbow like the ones you see in the sky using materials you probably have on hand.

How to Make a Rainbow

Here’s what you need:

• clear glass of water
• a piece of white paper
• masking tape
• flashlight
• (possibly will need a can or jar)

How to Make a Rainbow

1. Cover the flashlight with two pieces of tape leaving a slit in the middle.
2. Shine the flashlight through the glass of water onto the piece of paper.
3. The rainbow should appear on the paper.  {Turn off the light to see it better.}
4. You may need to sit the glass on top of a can or jar of peanut butter {in my case} to raise the glass up higher.
5. Play with the angle of light shining through the glass until you get a good rainbow.  For me, shining the light near the top of the glass {by the rim} worked the best.

The Science Behind It

The light from the flashlight (white light) contains all the different colors of light (Red, Orange, Yellow, Green, Blue, Purple {or Indigo and Violet if you prefer}).  When you shine the light through the water or onto the DVD, it refracts (bends) and splits into the different colors.  This is because the different colors (wavelengths) of light behave slightly differently as they travel through the water and glass.

More Rainbow and Play Ideas

• Make rainbow foam eggs with a simple science reaction.
• For more flashlight fun, check out Shadow Play Science.
• Use a rainbow to learn colors in this fun toy scavenger hunt.
• Use a little science to make rainbows in milk.

Then, for even more rainbow awesomeness, check out all of the rainbow posts below.

This post was originally published on April 25, 2012. The Outlaw Mom organized a blog hop to bring you our favorite ideas for kids involving rainbows.

Enjoy the rainbows!