Disappearing Rainbow Science Experiment

Summer is the perfect time to explore hands-on science with your kids — especially when it’s fun, colorful, and can be done with household supplies. If you’re a homeschool parent looking to blend science learning with a little magic, this Disappearing Rainbow Science Experiment is just the thing.

This quick and fascinating activity teaches your child about light refraction — the bending of light as it passes through different materials — all while creating a vibrant rainbow that seems to vanish before your eyes!

In this post, we’ll explain how to do the rainbow science experiment, outline the science behind the experiment, give you some ideas on how to extend the learning to other subjects, and ways to expand this experiment into a mini-lesson for your homeschool. Whether your family homeschools through summertime or takes a break, this experiment is an ideal one to keep the learning going through the summer season.

🧪 Disappearing Rainbow Science Experiment

Recommended Ages: 4–10
Subject Areas: Science (Physics), Art
Time: 10–15 minutes
Mess Level: Low

Supplies You’ll Need:

Large clear container (bowl, pan, or bucket)
6–8 cups of water
1 piece of white cardstock or thick paper
1 gallon-sized resealable plastic bag (Ziploc works well)
Markers: red, orange, yellow, green, blue, and purple

Instructions:

Prep the Materials
Gather your supplies and find a flat surface near a window or under a good light source. Natural sunlight works best for this experiment.
Draw Your Rainbow
Using the markers, draw a bold rainbow on the white cardstock. Be sure to use bright colors and draw near the center of the page.
Seal it Up
Slide your rainbow drawing into the resealable plastic bag. Seal the bag completely, pushing out as much air as you can.
Time for the Magic
Fill your large container with 6–8 cups of water. Slowly dip just the bottom of the baggie (with the rainbow inside) into the water. Hold it still and observe what happens.
Watch the Rainbow Disappear!
As the light passes through the water and the baggie, you’ll notice the rainbow starting to vanish from the bottom up!

What’s Happening Here?

Refraction!
This disappearing rainbow science experiment is a simple way to show how light bends (or refracts) when it moves between different materials — like air, plastic, and water.

When light travels through air, it moves quickly. But when it enters a denser material like water, it slows down and changes direction slightly. This bending of light changes how we see objects, including your child’s carefully drawn rainbow! As the angle of the light shifts, parts of the image seem to fade or disappear altogether.

This is the same principle behind fun optical illusions, bent pencils in a glass of water, or the sparkle of a swimming pool on a sunny day.

Extend the Learning

Ask your child questions like: “What do you think would happen if we used wax crayons instead of markers?” or “Would this work with a mirror?”
Try variations: What happens if you tilt the bag? Use a flashlight instead of sunlight? Draw a different shape?
Introduce vocabulary like: refraction, optics, medium, angle of incidence (for older learners).

Cross-Curricular Connections

Art: Practice color theory by mixing markers or creating your own rainbow pattern.
Language Arts: Have your child write a short “Rainbow Mystery” story explaining where the rainbow went.
Math: Measure how much of the rainbow disappears at different angles or depths.