Why is it purple? 2 ways to experiment with color blending (without paint!)

Color is all around us, but what makes each color unique?

Sweet Pea is into ‘speriments (experiments) and colors (specifically matching), so I wanted to expand on that by having her see what happens when colors mix together.

Science + Fine motor + sensory (touch) = lots of fun for both kids!

Buddy Boy enjoyed watching the fizzing (colored vinegar dropped into baking soda). His is the marble-type one in the front and Sweet Pea’s is the mushy one because she started squishing it. We’re leaving this until tomorrow to see what happens and play some more.

To do activity, you’ll need:

– baking soda

– vinegar

– food coloring, egg dye (Easter clearance!), or maybe liquid water colors

– containers for the colored vinegar and a tray for each child

– Droppers of some sort. If your little one is old enough, spoons might work or maybe even medicine syringes

Invitation to play- simple science for toddlers and preschoolers, easy preschool STEM activity. Exploring with color blending through science, preschool STEM, toddler STEAM activity. Simple science invitation to play activity from Lessons and Learning for Littles.


Ask your child to put the colored vinegar on the baking soda (which was spread out on the tray) using the eye dropper or whatever took you’re using. Talk about what happens (chemical reaction between the vinegar and baking soda, which can be seen and heard).

Talk about it and discuss what you’re seeing- What happens when another color is added to the first color? How long does it fizz for when vinegar is added? What does it feel like? Smell like? What color does combining blue with yellow make? Blue and red? Etc.

If your child is old enough, before you begin, you can make a prediction and then check it as you conduct the experiment… just a simple, “what do you think will happen?” Wait for a response. Follow with a “why” or “how so” type question to expand on your child’s reasoning and dig a little deeper. Then, as you do the experiment, remind your little one about their prediction and talk about how it compares to what actually happened.

Idea #2: Translucent shapes/items

Another idea to see colors “blend” together is to use a light box (or bright window) and something translucent but colored. We had shapes that we used. Magnatiles would work nicely too. When the colored pieces are layered, we can see what color they make when they’re blended together.

This would be a great chance to make predictions. “Which  do you think we’ll make when we put the blue tile over the yellow tile?” “What will happen if we now place the yellow tile over the blue tile?” Note: you could also use the shape names if you’re using shapes. This is a great chance to talk about what makes each shape unique (properties of each shape), count the number of sides, etc. The light box isn’t needed, but makes it more fun because it’s something different.

Tips for Two:

I did these activities by myself with an almost 3yo and a 15 month old with them both sitting in their booster seats at the kitchen table. Buddy Boy (15months) loved watching me add the vinegar to the baking soda and seeing what happened. He was only interested in the tiles (I gave him only big ones, as some where small enough to be choking hazards) and light box for a few minutes, so I gave him Duplos instead and that kept his attention longer. It can be a lot of work going back and forth between the two, but we had fun and I’m pleased that our first real science experiment with all 3 of us went so well! It’ll get even easier with practice. 🙂 I suggest having a back up activity readily available for whichever child you think will be “done” first. And a towel. In case the vinegar spills. Ours didn’t, but you never know…
Happy experimenting!

Connie 🙂