Rainbows are one of the most beautiful natural wonders and can teach us so much about color science for kids. After this five minute science activity everyone will walk away with their own magnificent rainbow paper that can be enjoyed year-round, rain or shine. And if you love this activity you will want to check our Five Minute Science series and our compilation of St. Patrick’s Day science experiments that include several more ways to make and play with rainbows!
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To make rainbow paper we gathered a few quick supplies:
- A bowl filled with water
- Clear nail polish
- Rectangles of black construction paper or black card stock (about 3-5 inches long on the sides)
- Paper towels
The rainbow paper experiment is simple, but it does take some patience to get it just right. I made dozens of pieces of rainbow paper and about half of them turned out. Then my six-year-old daughter swooped in and made several stunning pieces right in a row. Don’t worry, I made a video of her doing it below so we can all copy her fine technique!
I have had some readers express concern about the fumes nail polish creates. I suggest doing this experiment in a ventilated area with good air circulation. The exposure to nail polish is so brief that it shouldn’t cause any problems, but if you have a child that is especially sensitive to strong smells it may be best to either do this experiment outside or skip it altogether.
How to Make Rainbow Paper
When my daughter was ready, all she did was drip one little drop of nail polish into the bowl of water.
She waited a couple of seconds and then dipped a piece of black paper into the water and pulled it out again. That’s it!
We set the pieces of rainbow paper onto paper towels to dry. It was amazing to see how different each piece turned out!
I have also had success with placing the paper under the water first and then dripping one drop of clear nail polish on top of it. The nail polish disperses across the surface of the water within a couple of seconds. Once the nail polish spreads out, it’s safe to pull the paper out of the water, coating it with a thin film of clear nail polish.
Experiment to see which technique works best for you!
The nail polish dries quickly on the surface of the water, which creates a film that won’t stick to the paper. To do this activity successfully it needs to be done quickly. Be sure to dip the paper into the water within 10-15 seconds after the drop of nail polish goes in.
If the nail polish does create a dry film on top, simply scoop it off and try again more quickly!
Easily print these directions for quick reference by clicking the button below:
We did this experiment several times with several pieces of paper. It was fascinating to see how each piece came out so differently!
Once the paper is dry (this only takes a few minutes) tilt the paper in different directions to see the rainbow patterns appear. Hold it next to a sunny window for best results!
The Science Behind Rainbow Paper
When you dip the paper into the water it gets coated with a thin layer of nail polish. The rainbow colors you see are caused by thin-film interference. (Read a more detailed explanation of thin-film interference on Wikipedia.)
You will notice that the colors on the paper change as the you tip the paper back and forth. This happens because light hits the paper at different angles as you tip it.
The colors of the rainbow vary with the thickness of the nail polish on the paper. This is why each piece of rainbow paper is varied and unique!
This is the same effect you will see when oil mixes with water on the road on rainy days. Thin film interference is also visible on the surface of soap bubbles at just the right angle to the light.
There are many creative methods for making colored paper. Here are a few more of our favorite STEAM projects for making different kinds of rainbow papers with supplies we already have at home:
Each piece of rainbow paper is sturdy and resilient. They can be cut up and used for a rainbow paper craft such as a Mother’s Day card, a valentine, or paper wings on an insect.
Check out the video of my daughter making her fabulous rainbow paper to see her technique! (She actually made most of the best pieces I photographed for this post.)
Science for Kids All Year
If you like simple experiments for kids, you are going to LOVE receiving them on your doorstep each month! The Little Passports Science Expeditions kits are full of science experiments related to themes that excite kids like rockets, forensic science, vision, caves and crystals, hydrology, and more.