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