A toddler science experiment that really delivers

Updated: Apr 29

We all now know that "homeschooling" toddlers is a FULL time job and ranges from negative to mild success on most days. And trying to actually "teach" them something too? Oof. It's more than most of us can deliver.

I've begrudgingly Googled "toddler science experiments" A LOT and many require ingredients I don't have or just seem too difficult/messy for what I'm willing to try in my kitchen. Sorry kids.

BUT - the rainbow walk caught my attention because 1) rainbows are very IN 2) you only need cups, water, food coloring, and paper towels. I can do this. The experiment is fast to set up and then you get to watch it evolve over several days which turned out to be fun for my kids observe. Lots of "whooooooas" have been heard.

Here's how it goes:

Step 1: Grab your supplies

  • 6 short glasses

  • 6 paper towels

  • Red, blue, and yellow food coloring

  • Water

Step 2: Set it up

Arrange your glasses in a circle. Then fold your paper towels in thirds and connect the cups with them (basically making an arch between each cup). You don't want the paper towel arches to be too tall above the glasses so rip or cut them down till they bend just over the top of the glasses. Now take the paper towels out and set them aside.

Step 3: Add color + water

In three of the glasses (leave an empty glass between each), add 10 drops of food coloring. One glass should have 10 drops of red, one with 10 drops of blue, and one with 10 drops of yellow. Then fill three glasses with food coloring with water until each glass is about 3/4 full. Continue to leave the other three glasses empty.

Step 4: Assemble your bridge

Put the paper towels arches back in the glasses so that all six glasses are connected. Begin to watch the magic.

Step 5: Check in and see the color magic happen

Within a few minutes you'll see the colors making serious progress traveling up the paper towels. Within a few hours you'll have the first drops of colored water appearing in the empty cups. Within 24 hours the water will have leveled out and be equal in each of the six cups. And after a few days, the water and paper towels will have transformed so you now have 6 distinct colors and a very vibrant rainbow!

As a parent that usually has to pretend to like the things my kids like, I was really amazed by this activity. And I'm not even TOO mad that I've been instructed it stay on our kitchen island "as long as the boy has his tree in the Giving Tree."

And if you want to layer in some "teaching" - you can talk through primary colors you start with and the secondary colors that appear later through color mixing. That's the easy part, you've got that in the bag.

You can also tell them about capillary action, the magical process that allows the colors to "walk" up the paper towels. Basically the water is able to travel through the gaps in the paper towel's fibers. The gaps act like capillary tubes and pull the water upward. This is the same process that allows water to climb from a plant’s roots to the leaves at the top of the plant or tree. Boom - you just taught a science lesson.

Hope this one gives your family just as much satisfaction as it gave mine!


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