1 Add 4 small cups of water to 7 small cups of cornflour in a bowl. 2 Mix it around with your hands until it becomes a gooey mixture. 3 Plunge your hands right into the mixture and then lift them upwards so that the mixture drips through your fingers. 4 Grab some of the mixture and quickly roll it into a ball using the palms of your hands. 5 Slap and prod the mixture in the bowl. Isn’t this mixture the strangest stuff you’ve ever seen? When you let the mixture drip through your fingers, it behaves like a liquid. Yet when you roll the mixture and slap it, it behaves like a solid. But when you stop rolling it, the mixture drips through your fingers like a liquid again! This can mean only one thing. The mixture is both a liquid and a solid. When it is left alone, it flows like a liquid. But when you treat it roughly by slapping it or rolling it, you are forcing the water molecules into the cornflour particles and it behaves like a solid. When you stop applying pressure, the molecules can relax and the material flows like a liquid again.

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