Rainbow Rain Science Experiment

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Today’s lesson is all about having fun with Earth Science!

The Rainbow Rain experiment is a fun, colorful Earth Science experiment that shows the water cycle and how rain is formed. Many, if not all supplies needed for this experiment can be found at home, making it an easy and fun way to teach your child Earth Science.

The next time you see rain in the forecast, be sure to refer back to this experiment and watch the clouds fill up with water!

progression of the rainbow rain experiment
Progression of the Rainbow Rain experiment

How to make the Rainbow Rain experiment

Supplies you will need

For the Rainbow Rain experiment, you’ll need:

  • Wide, clear container (vase, jar, wider mouth cup)
  • Foam shaving cream
  • Food color
  • 7 smaller containersOpens in a new tab. for rainbow colors
  • Optional: pipettesOpens in a new tab.

Before you start

If you’re allowing your preschooler to handle water, it’s best to put a towel under your experiment.


Here is how to do the Rainbow Rain experiment with your toddler:

Step 1: Add water to your larger container

We filled our container about 3/4 of the way full to leave enough space for the shaving cream in the next step.

You’ll want to add enough water that you are able to clearly see as the colors start to fall through the shaving cream and into the water.

Step 2: Add the shaving cream on top of the water in large container

large container with shaving cream in rainbow rain experiment
Adding about 1-1.5″ of shaving cream to the container

Give your shaving cream a good shake and start adding it on top of the water in your large container.

Try not to create an overly thick layer of shaving cream. The thicker the layer, the longer it will take to see the results (and you may have to end up adding more rainbow water). A good 1-1.5″ thick layer of shaving cream should do the trick.

Since I prefer it to be uniform on top for when we add our colors, I took a spoon and gently evened out the top of the shaving cream with it. You don’t have to do this; it was just my type A personality kicking in!

Step 3: Create your rainbow colors

smaller containers with each color of the rainbow
After adding each color of the rainbow in smaller containers (indigo and violet look very similar in this photo!)

This part is fun and a good lesson inside a lesson to talk about colors with your toddler.

We used these small mason jarsOpens in a new tab. that we already had on hand from making baby food.

Using 7 of these small mason jars, we used a picture of a rainbow to talk through all of the colors of the rainbow. My toddler got to add water to each mason jar and I added the food coloring.

We talked through the colors that came with our food color kit (red, blue, yellow, and green) and how to make the other colors of the rainbow with what we had! We do this sometimes with her MagnaTiles (combining colors), but she’s never seen it in action like this.

Here are the color combinations using a standard box of food colors:

  • Red: comes in a food color box
  • Orange: 1 red drop + 1 yellow drop
  • Yellow: comes in a food color box
  • Green: comes in a food color box
  • Blue: comes in a food color box
  • Indigo: 2 blue drops + 1 red drop
  • Violet: 1 blue drop + 1 red drop

Step 4: Add rainbow colors to the shaving cream

For this step, we had one pipette for every color to ensure we did not mix any colors together.

If you do not have pipettes, you can carefully pour the colors onto your shaving cream for the same effect.

My preschooler was able to add the colors to the rainbow with a little bit of assistance from me. She squeezed the bulb while I held the pipette and helped direct the flow.

Step 5: Watch it rain rainbows!

Depending on how thick your shaving cream is and how much rainbow color water you added, you’ll start to see rainbow rain falling in just a few minutes.

If you enjoyed this experiment, check out how to make a cloud in a jar, or even make your own ocean wave!

The science behind the Rainbow Rain experiment

The Rainbow Rain experiment is a great experiment to learn about meteorology and the water cycle!

For the parent

In this experiment, we are essentially creating a version of the water cycle to make rain.

The water in the wide container represents the atmosphere that we live and breathe in. The shaving cream represents a cloud we can see in the sky.

Here’s a good explanation of what is happening from NASA’s Global Precipitation Measurement:

Water molecules are heated by the sun and turn into water vapor that rises into the air through a process called evaporation. Next, the water vapor cools and forms clouds, through condensation. Over time, the clouds become heavy because those cooled water particles have turned into water droplets. When the clouds become extremely heavy with water droplets, the water falls back to earth through precipitation (rain, snow, sleet, hail, etc). The process continues in a cyclical manner.


Using our rainbow water colors, we are skipping ahead in the water cycle to create the water droplets in the cloud prior to precipitation.

Once our shaving cream cloud becomes too saturated with our rainbow water, we start to see rainbow rain!

For the child

The Rainbow Rain experiment is all about seeing how the rain forms inside of clouds.

When the sun heats up the ground and bodies of water, it causes the water to evaporate, or create tiny particles of water that rise into the sky. These tiny particles of water make their way up to where you see clouds.

Once the water travels up to where clouds form, those tiny particles of water condense into the clouds we can see.

As the clouds fill up with more and more tiny particles of water, they become so heavy that the cloud cannot hold the water anymore.

When that happens, it starts to rain!

FAQ about the Rainbow Rain Experiment

How much shaving cream should I add to my container?

One thing to keep in mind when adding the shaving cream to your container is that, the thicker the layer of shaving cream, the longer it will take to see the results.

We added about 1-1.5″ of shaving cream to our container.

How can I get my toddler involved in the Rainbow Rain experiment?

There are lots of ways! Here are a few that we did:

Let your toddler add the water and mix the colors for each rainbow color

Little ones LOVE pouring into containers!

I used a small containerthat had a spout on it that she could hold with one hand and let her pour into each small mason jar.

Let your toddler use a pipette to add the rainbow colors to the cloud

Pipettes are optional, but almost essential if you want your little one to get involved with adding the colors to your cloud.

I let her squeeze the bulb and gather the colored water into the pipette. Once she was ready to add the color to the cloud, I gently guided the pipette as she squeezed the water out.

To see the experiment from start to finish, check out our video for the Rainbow Rain experiment:

Rainbow Rain experiment

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