Punching Corn Flour

Is it a liquid? Is it a solid? It is possible for it to be both?

What you need:

  • corn flour
  • water
  • large bowl

What to do:

  1. Put 2 cups of corn flour in a bowl.
  2. Add 1 cup of water. Use your hands to mix together. It will be sticky.
  3. Dip your fingers in slowly and pull them out, letting the liquid drip off you.
  4. Remove your hands from the liquid.
  5. Punch the mixture as hard as you can.

What happens:

When you dip your fingers into the mixture, it behaves like a liquid. When you punch the mixture, it will behave like a solid. That’s because this mixture is what’s called a non-Newtonian fluid, meaning it exhibits some properties different to other liquids, like becoming more viscous when more pressure is applied. So when you slowly put your fingers in to the mixture, it does what you’d expect a liquid to do. When you punch it, you are applying more pressure, and the molecules inside it get trapped and can’t move around as much, so it seems like a solid.

 

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