This post is part of the 31 days of STEM activities for kids post. Read the rest here!
Today’s experiment was our favorite science experiment of the month. We loved how the cornstarch mixture became a solid and a liquid at the same time.
Cornstarch and water mixed acts both like a solid and a liquid. Cornstarch and water is a suspension mixture with a solid dispersed into a liquid. When you press the mixture quickly, the starch molecules close together. This causes the water to get trapped between the starch chains and create a semi-rigid structure. When you press slowly, this starch chain “block” doesn’t happen and the mixture flows like a liquid.
Because the viscosity of the mixture changes with force rather than heat, the cornstarch mixture is known as a non-Newtonian fluid.
For this experiment you will need:
- 1 box of corn starch
- A large bowl
- Food coloring
Mix the corn starch and the water together at a ratio of about 10 parts starch to 1 part water. Start the mixture by adding about ½ of a cup of cornstarch to about 1 cup of water. Play with the mixture until it reaches the consistency that you want. Monkey and Bo liked it to be somewhat runny, but still firm enough to seize up when they hit the mixture.
Aside from making a GINAT mess all over the kitchen, this was the girl’s favorite science experiment. They thought being able to have a solid and a liquid at the same time was really fun. Monkey in particular liked how when she washed the goo off her hands, it came off so easily.
We tried making the mixture dance on a speaker, but we were not successful with our tiny computer speakers.
Have you ever made cornstarch quicksand? It’s a lot of fun, but be prepared for lots of mess!
Read the other posts in the 31 days of STEM activities for kids series!
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