Ok, so this has different names but we’ve always called it oobleck. It is a lot of fun and quite an intriguing science experiment! All you will really need is cornstarch & water. You are welcome to add food colors in it if you wish, but I have never bothered.
Mix the cornstarch and the water together until it is a stringy consistency. Fluid but not watery. (think a thick cream soup) Slowly put your spoon (or finger!) into the mix…..the mixture will attach to your finger as your would expect.
Now use the spoon (or your hand!) and hit the mixture hard. Notice what happens (or what doesn’t happen!?)
Check out (one of the) world’s largest oobleck pools!
What happens? The force causes the molecules to bond together and neither your hand nor the spoon should get dirty. The gooey mix will become hard when you smack at it, and then fluid and stick if you slowly insert something into the bowl.
It’s a really neat project. I have always had middle school kids especially love this as it peaks their interest into science in a simple way! This also makes a great summer camp activity! Fill up a kiddie pool with oobleck and watch the kids’ faces as they learn and experiment!