Do you ever wonder how humans see color? Through this “Rainbow Paper” activity, we will create a beautiful rainbow that they can hold in the palm of their hand. We will also learn about what happens when light waves hit a thin-film interference—a natural phenomenon that involves reflected light.

Caution: We highly suggest to do this activity in a well ventilated area due to nail polish fumes. The use of nail polish is very brief (only one drop needed per black rectangle), but it is better to take precautions.


Concepts to explain to your child (during the activity)

A thin-film interference is the reason why the colors on our handmade rainbow are possible to see.
Light waves reflect onto the surface and create these colors on our coated paper.
The visible spectrum is the portion of the electromagnetic spectrum that is visible to our human eyes.


Note: The nail polish dries quickly after a drop is put into the water, and this creates a film that does not stick well on the paper. Make sure your child does this process quickly. As soon as the drop of nail polish hits the water’s surface, wait 10-15 seconds. Then dip the paper. If the nail polish creates a dry film on top, scoop it off and try again! Please assist your child with this activity if needed. You can decide how much information you want to share with your child based on age, ability, etc. All information written on this newsletter is for grades K-5.


Did You Know?

Different wavelengths reflect off an object and back to our eyes! A wavelength is the measured distance between two of the same points on two back-to-back waves. For example, one wavelength is like climbing from the top of one hill to the top of another hill. Through this activity, we will experiment with the colors reflected back to our eyes by wavelengths of light.


Materials:

  • 1 Small to medium sized bowl filled with water
  • 1 Bottle of clear nail polish
  • 1 Ruler
  • 1 Pair of safety scissors
  • Black construction paper/card stock (about 3-5 inches long on the sides)
  • Paper towels

Making the Rainbow

  1. Take your black paper and measure out 4-6 rectangles that are 3 in. x 5 in. Cut up as many rectangles as you can.
  2. Fill your bowl with water, and place the bowl carefully on a table.
  3. Open up a bottle of clear nail polish and let a drop fall into the water.
What do you see? Does the drop of nail polish fall to the bottom of the bowl? Or does it cover the surface of the water?

4. Wait 10-15 seconds. The nail polish should be coating the water.

5. Take your black rectangle and dip it in the bowl. Make sure the liquid spreads across the whole paper, then take it out and place it on a paper towel.

How does the paper feel? What does it look like?

6. Repeat this process until all of your black rectangles have been dipped into the liquid. Make sure to add a drop of nail polish into the bowl before dipping your paper.

7. Wait a few minutes for the paper(s) to dry.

Do they look different from the wet paper? If so, what difference do you notice?

8. Tilt the paper in different directions.

What do you see? Hold the paper to a sunny window. What do you see now?

How Our Handmade Rainbow Relates to Science

When the black paper is dipped into the nail polish and water mixture, a thin-film interference is created.

Have you ever seen a puddle or a bubble under the sun? What did the puddle or bubble look like?

A thin-film interference is the reason why these colors are possible to see. Light waves reflect onto the surface and create these colors on our black paper. A light wave is a form of moving energy that is made of tiny microscopic particles called photons. Light waves can also be called electromagnetic waves because they make up the electromagnetic spectrum.

Electromagnetic means that the waves are both electric and magnetic.

The electromagnetic spectrum lines up all of the electromagnetic waves based on their wavelengths.

A long wavelength is considered to have low energy. Why is that?
A short wavelength is considered to have high energy. Why is that?
Can we see waves that are outside of the visual spectrum (ex: microwaves or x-rays)? Why or why not?
What colors do you observe? Are they in the order of the rainbow spectrum?

In this “Rainbow Paper” activity, we focus on what is visible in the visible light part of the spectrum. The visible spectrum is the part of the electromagnetic spectrum that is visible to our human eyes.

Do you see all of the colors in the chart on your handmade rainbow? What color(s) do you see the most? Why do you think so?

Conclusion

Through this “Rainbow Paper” activity, we learn about how light reflects into our eyes through a thin-film interference. We find out how the electromagnetic spectrum includes visible light, which allows us to appreciate the colors found on our handmade rainbow when light hits the surface.


Learn More

Rainbow Paper | Color Science for Kids

NGSS

1-PS4-3.Plan and conduct investigations to determine the effect of placing objects made with different materials in the path of a beam of light. [Clarification Statement: Examples of materials could include those that are transparent (such as clear plastic), translucent (such as wax paper), opaque (such as cardboard), and reflective (such as a mirror).] [Assessment Boundary: Assessment does not include the speed of light.]