This is basically cornflour (cornstarch) and water but it has some VERY interesting properties.
What you need
- Large mixing bowl
- Measuring jug
- Cornflour (450g / 16 oz)
- Water (475ml / 16 fl oz)
This can be a little messy so a plastic table-cloth and an apron may be sensible
Place the cornflour in a mixing bowl and add the water. Stir the mixture with your hands until it is smooth and has the consistency of thick cream
It should be able just to pour through your fingers when held in your open hand.
The actual ratio of cornflour to water is not critical so feel free to adjust it.
Experiments you can do
Hold the mixture in your hands and it will flow through your fingers.
form it into a ball and keep squeezing it and it will behave as a solid… until you release it and it will then flow through your fingers again!
Try thumping it with your fist: it will be quite solid.
Push your fingers down into it slowly and it will behave as a liquid.
How it works:
When you mix cornflour with water, the large cornflour particles remain suspended (float around) in the liquid.
When you stir the mixture slowly it acts like a liquid because the starch particles can slide past each other.
When you strike the mixture hard or push it quickly the large starch particles get locked together, trapping water between them.
As soon as the pressure is released they move apart and can flow again.
Sir Isaac Newton worked out how a liquid ought to flow but this mixture does not follow these rules.
It is known as a non-Newtonian fluid
This is similar to how quicksand behaves. Quicksand happens when sand is suspended in lots of water.
if you are standing in very wet sand at the beach and push your foot slowly it can move through the sand.
As soon as you move your foot quickly the sand particles lock together.