I can promise you that mixing colors with cornstarch water is one of those perfect kids’ activities that keeps kids busy for hours. Wonderful, wet, and messy, adding a fun touch of color mixing to cornstarch water (sometimes referred to as “oobleck”) is a perfect way to stay cool on a hot summer day.
While play clothes are essential for this messy kids’ play idea, the mess of the cornstarch water does easily wash away with a hose. (Doesn’t that sound like a fun way to finish up the outdoor play time?)
How to Make Cornstarch Water (“Oobleck”)
Using a cheap dollar store plastic vegetable/fruit tray as a color tray, I placed cornstarch (around a 1/4 cup) in four compartments of the tray. I then took around an 1/8 cup of water plus a couple drops of food coloring for the primary colors and mixed it with each compartment of cornstarch to make cornstarch water (“Oobleck”). I also made a big tub of white cornstarch water for mixing.
Add the water slowly and mix with a spoon or your fingers and stop adding water when the texture can be rolled into a ball into your hands but is gooey when you let go. If you have never made cornstarch water, be prepared for a fun sensory experience.
While the cornstarch water is easy to wash away with a little bit of warm water, I would recommend play clothes since the food coloring could stain clothing.
Cornstarch water is not only fun to play with but can be a great opportunity for a science lesson. Here is a great explanation on Science Bob of the scientific properties of cornstarch water: How Oobleck Works.
Setting Up Your Color Mixing Station
Once you have your primary colors of cornstarch water set up, I recommend guiding your kids by helping them mix together the primary colors with clean spoons to create the secondary colors of the rainbow. Older kids may enjoy taking that science experiment to a new level by then adding secondary colors to primary colors to create tertiary colors.
You may want to add a little bit more food coloring to give a vivid hue to your color mixing. Be aware though that more vivid colors may also result in more staining of clothes. I typically have no problem rinsing out lighter shades from clothing.
Once you have guided your children in mixing colors to create secondary and/or tertiary colors, it’s time to stand back and let whatever mess occurs happen. I think kids learn more sometimes through just experimenting on their own without adults hovering over them.
Let your kids mix all the colors together and see what will happen (yep, it will be a nasty brown blob). Try bouncing and experimenting with the cornstarch water on different outdoor surfaces.
When you are done, use the naturally warmed hose water to wash everything off (while being careful that it’s not so hot it’ll burn the kids.)
Plan on doing the activity again. My kids loved it and I’m sure yours will too!