Create a liquid that turns into a solid when tapped. How does it work? When you mix corn starch with water, the large corn starch particles remain suspended in the liquid. When you stir the mixture slowly, it acts like a liquid because the suspended particles have time to move past each other. When you put sudden stress on the mixture, the water quickly flows out of the area, but the particles do not have enough time to move out of the way – making the mixture act like a solid.
Sir Isaac Newton described how ‘normal’ liquids or fluids behave. He observed that their viscosity only changes with variations in temperature or pressure. In non-Newtonian fluids, their viscosity also depends on the force applied to the liquid.
Add the corn starch to the bowl.
Add water slowly to the mixture, stirring in one tablespoon at a time, until all of the powder is wet.
Continue to add water until the corn starch acts like a liquid when you stir it slowly – but when you tap it with your finger it becomes hard.
Scoop the mixture into your hand and slowly work it into a ball.
As long as you keep pressure on it by rubbin it between your hands, it stays solid. Stop rubbing, and it melts into a puddle in your palm.