You’ll need

  • A mixing bowl
  • Cornflour made from corn (not wheaten cornflour)
  • Food colouring (optional)
  • A jug of water
  • A stirring spoon

The amount of cornflour will depend on how much slime you want to make. A 300 g packet of cornflour will make about 2 cups of slime.

What to do

  1. Gather your materials on a flat surface, like a desk or kitchen table.
  2. If you like, add a few drops of food colouring to the water and stir it well.
  3. Put the cornflour in the mixing bowl.
  4. Pour a small amount of the water into the cornflour and stir.
  5. Keep adding small amounts of water, stirring slowly each time, until a thick slime forms.
  6. Stir the slime slowly with the spoon. Notice how the spoon moves easily through the slime.
  7. Now try to stir the slime really fast. Notice what happens.
  8. Remove the spoon from the bowl. Make a fist and punch the surface of the slime. The slime will feel rock‑hard, and your fist won’t go through it.
  9. Now, slowly lower your fist into the slime. Your fist will sink into the gooey, sloppy slime!
  10. Keep your slime in an airtight container in the fridge, and it will last up to 2 weeks.

Questions to ask

What does the slime feel like when you hit it? What about when you touch it slowly?

What happens if you try to pick up some slime?

Do other household ingredients work in the same way? Try mixing plain flour with water to see if the same thing happens.

What's happening

Some fluids get thicker when they are stirred, and some get thinner. Cornflour slime is a fluid that gets thicker when it is stirred.

When cornflour slime is stirred or punched, the cornflour particles lock together, and the slime feels like a solid. When more force is applied (by stirring more quickly or punching harder), the mixture feels more solid. When less force is applied, the cornflour particles have time to move around each other, and the mixture flows like a fluid. This is what happens when you stir the slime slowly, or gently place your hand into the slime.

Did you know

Fluids that thicken when stirred have more uses than just making slime! They can be combined with strong fabrics to make bullet‑proof vests. After being soaked in the fluid, the fabric can withstand the high impact of a bullet. However, slow-moving objects pushing on the fabric will not cause the fluid to harden. This means that the fabric is comfortable to wear and is more protective against the sudden impact of a bullet than against a slower-moving object such as a knife.