- Cornflour
- Water
- Bowl
- Spoons (tablespoon & teaspoon)
Method
- Put 4 tablespoons of cornflour in the bowl
- Add the water, small amount at a time, until the cornflour resembles a very thick liquid
- Try stirring the cornflour slowly and then quickly. Is it a liquid or a solid.
- Put some of the mixture in your hands and roll it into a ball; what happens when you stop rolling it?
What is going on
You end up with a really strange mixture. Put some mixture in your hands and roll it into a ball, but when you stop rolling it, it turn back into a liquid.
The Science behind it
The cornflour does not dissolve in the water – it creates a suspension called a colloid. The cornflour particles are very fine and roll over each other, which means that the mixture acts like a liquid. However, when energy is added to the mixture (by stirring or rolling in the hand) the particles of cornflour lock together and the water between the particles is pushed out of the way, so the slime behaves like a solid.
Try adding food colouring to created different coloured slime – but be warned – this can get very messy!