Exploring Non-Newtonian Fluids

Introduction

Slime isn’t just fun—it’s a great way to explore chemistry and physics! In this activity, Scouts will make their own slime and investigate non-Newtonian fluids, which change their behaviour under pressure. Depending on the type of slime made, Scouts will either observe a chemical reaction (borax and PVA glue slime) or a simple mixture behaving strangely (cornflour slime, also called oobleck).

Scouts will also test how different ingredients affect slime’s stretchiness, viscosity, and elasticity, making this a hands-on science experiment!

What you'll need

• For Oobleck Slime:

  • Cornflour (about 2 cups per person)
  • Water
  • Bowl and spoon for mixing
  • Food colouring (optional)

  For Borax and PVA Slime:

  • PVA glue (school glue)
  • Borax solution (diluted sodium tetraborate) OR contact lens solution & baking soda (alternative)
  • Water
  • Mixing bowls & spoons
  • Measuring cups
  • Food colouring, glitter, or sequins (optional)

  For Safety and Clean-up:

  • Gloves (optional, for handling slime)
  • Paper towels and wet wipes
  • Airtight containers (for taking slime home)
  • Handwashing station

Activity

• Make the Slime:

  • Follow the below instructions for the chosen slime type, mixing the ingredients carefully
  • For borax slime, add glue and mix with borax solution until it forms a stretchy, solid slime
  • For oobleck, slowly add water to cornflour and mix until it becomes thick and behaves strangely

Oobleck Slime

Oobleck is a liquid when held gently but turns solid when you apply force. It demonstrates non-Newtonian fluid behaviour—meaning it doesn’t follow normal liquid flow rules.

1. Pour 2 cups of cornflour into a mixing bowl.
2. Slowly add 1 cup of water while stirring.
3. Keep mixing until the consistency is thick but still flows slowly.
4. If it’s too dry, add a little more water. If it’s too runny, add more cornflour.
5. Add a few drops of food colouring and mix (optional).

Borax and PVA Glue Slime

This slime is a polymer, meaning its molecules are linked together like a stretchy net. The borax cross-links the glue’s molecules, creating a solid but flexible slime.

1. In a bowl, mix ½ cup of PVA glue with ½ cup of warm water.
2. Add food colouring and mix well (optional).
3. In a separate cup, dissolve 1 teaspoon of borax in ½ cup of warm water.
4. Slowly add the borax solution to the glue mixture, stirring constantly.
5. The slime should start thickening immediately. Keep stirring until it forms a blob.
6. Knead the slime with your hands until it’s smooth and stretchy.
7. If it’s too sticky, add a tiny bit more borax solution. If it’s too stiff, add a little water.

• Experiment with the Slime:

  • Test viscosity (thickness) – Does it flow slowly or quickly?
  • Test elasticity (stretchiness) – How far can you stretch it before it breaks?
  • Try temperature experiments – Does cold slime behave differently from warm slime?

• Modify the Slime:

  • Change the ratio of ingredients – What happens if you add more water or more thickener?
  • Add glitter, sequins, or colours to personalise the slime

• Slime Games and Challenges:

  • Slime Races – Tilt a tray and see whose slime flows the fastest
  • Stretch Test – Whose slime stretches the furthest before breaking?
  • Slime Drip – Hang slime from a surface and see whose lasts the longest before dripping

Change the challenge level

Easier:

• Pre-measure ingredients for younger Sections
• Stick to oobleck, which is safer and simpler
• Focus on sensory play rather than scientific explanations

Harder:

• Try making different types of non-Newtonian fluids and compare them
• Research the science behind polymers and explain why borax slime forms
• Experiment with slime substitutes (e.g. contact lens solution and baking soda instead of borax)

Reflection