20 Minute Labs - Rainbow Paper

MAKE YOUR OWN RAINBOWS ON PAPER!

Everybody loves seeing a rainbow outside, but sometimes it goes away too soon. How about capturing a rainbow on a piece of paper so you can admire it anytime?

The beautiful array of colors is a wonder - it may seem like magic, but we can understand rainbows through science!

Put simply, rainbows occur when white light from the sun bounces off raindrops at a particular angle and splits into all the colors we can see.

In this month's 20 Minute Lab, we'll make a form of rainbow and attach it to shapes of paper using just water and nail polish!

WHAT YOU'LL NEED

• Dark-colored construction paper
• Dark-colored plate or bowl
• Water
• Clear nail polish
• Cloth napkin

LET'S GET STARTED!

1. Cut out some fun shapes from the construction paper. The shapes should be small enough to fit into your bowl or plate easily. We recommend making some regular rectangles to practice with first, then try some special shapes once you get the hang of the process.
2. Add water to the bowl.
3. Open the clear nail polish and hover the brush over the bowl of water, letting a drop fall into it. Recap the nail polish.
4. Watch as the polish spreads out into a film on the water! (This is easier to see in a dark-colored plate or bowl)
5. Quickly dip your paper shape into the bowl, letting the layer of polish cover it. Then take the paper back out again and remove any excess nail polish film from the sides. This takes some practice! Here's a visual of this step:
   
   
6. Place the shape on a napkin to dry.
7. Remove the remaining film from the water (you can just wipe it off on the towel or the edge of the bowl).
8. Repeat the process for each shape!  Try to find each of the colors of the rainbow on your shape: red, orange, yellow, green, light blue and dark blue!

WHAT'S GOING ON?

What made this rainbow effect on the paper? When the drop of nail polish fell into the water, it spread out and made a thin film.

Light from the sun is white, which is all the colors of the rainbow mixed together. When sunlight hits the layer of film, some rays bounce off the surface while others go through the film, reflect off the bottom, then bounce back out.

As waves of light travel through the film, they interfere with the waves that bounce off the surface. Since bouncing off the bottom takes a little longer, those waves get out of sync with the ones bouncing off the surface. 

Some of the waves cancel each other out (destructive interference) while others become stronger (constructive interference).

Because of destructive and constructive interference, some of the colors in the sun's white light cancel out and others remain visible and can be seen on your shape!  

Have you ever been in a parking lot and seen rainbows on the pavement? That's from oil - and the effect is the same as what you just did with nail polish and paper!

The same thing happens on the film on a soap bubble - at just the right angle, you can see the rainbow effect.

SHARE WITH US!

Let us know how your experiments turned out! Share your photos and results with us on Facebook, Twitter, Instagram, or send us an email to info@yellow-scope.com. We love getting your messages!

For more exciting experiments, check out our Yellow Scope science kits on the Shop tab of our website!