You will need:

- Starch
- Water
- A plastic container
- Food coloring, a wooden board, a hammer, and some nails for additional experimentation

Mix the water and the starch together in the container until the mixture turns viscous in its consistency. You’ll end up with what’s called a "non-Newtonian fluid." You can stick your fingers into it, but if you rap the surface of it with a fist you’ll feel that it’s actually hard. Place the wooden board on the liquid’s surface, and you’ll be able to drive a nail into it with ease as if it were solid. Yet dipping one corner of the board will lead it to sink to the bottom. To make the experiment more fun, you can add in some food coloring.

 

Watch the video here.