Slime time

Includes: Indoors, Technology and science

Activity time:
30 mins


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Ready to make some ooey gooey slime?

Making slime is a whole lot of messy fun. It's a great way to get girls thinking about science too.


Divide girls into groups. Rainbows and Brownies should be supervised at all times so how many groups you have will depend on how many volunteers are available. Then you can get started with making your slime: 

  1. Start with 200 grams of cornflour in a clean bowl and a jug with 200ml of water.
  2. Add a teaspoon of bicarbonate of soda to the cornflour. 
  3. Add water to the cornflour a little at a time, mixing with your hands as you go.
  4. Keep adding water until the mixture is the consistency you want. You can add more cornflour to make the slime thicker, or more water to make the slime thinner.
  5. Add a few drops of food colouring if you want to make coloured slime (why not make it the colour of your section?).
  6. Add a teaspoon of all-purpose contact lens solution and keep mixing and kneading your slime. (Contact lens solution includes boric acid. Although this recipe only uses a small amount, there are health risks when using excessive amounts. You should only use a very small amount of contact lens solution and don’t make excessive amounts of slime.)
  7. Keep adding teaspoons of contact lens solution until the slime is the desired consistency. The more you add the more solid the slime will get.
  8. Play with the slime! Try touching the slime gently and you’ll see it behaves like a liquid and flows through your fingers. Now try applying pressure to it. If you punch it quickly you'll see the slime solidify, or try picking up the slime and rolling it into a ball.

The science behind the slime

Slime is a non-Newtonian fluid. That means that when you pick it up, it will feel like a solid but then it’ll ooze like a liquid. The thickness of a fluid is known as its ‘viscosity’. The more viscous a liquid, the slower it would flow – think water vs. ketchup. You can change the viscosity of slime but squeezing it, stirring it or adding pressure. When you add pressure or hit the slime, the particles squeeze together making it feel more solid.

This method is just one way to try and make slime. There are loads of different ways to make different types of slime, so experiment with your girls and see which methods you like the best!

Planning checklist

Safety notes

  • A risk assessment should be completed before starting the activity.
  • Whilst the ingredients and the slime are non-toxic, they should not be ingested either before making the slime or after it has become slime - if it inadvertently is consumed, seek medical advice.
  • Contact lens solution includes boric acid. Although this recipe only uses a small amount, there are health risks when using excessive amounts. Only use a very small amount of contact lens solution and don’t make excessive amounts of slime.
  • Rainbows and Brownies should be supervised to undertake it.
  • Washing facilities should be provided and members should wash their hands after the activity. If any of the slime gets in their eyes, it should be carefully washed out.
  • If they take the slime home, it should be kept safely away from younger children and animals and should be disposed of responsibly.
  • Check for allergies to any of the ingredients before deciding to make slime.
  • To protect clothing and furniture (especially if you’re using food colouring) wear aprons and lay down bin bags or newspaper. Wear disposable plastic gloves if you’re using food colouring.


Girlguiding activity centres for Slime time