Materials Required
- White school glue (4 oz / 120ml)
- Baking soda (1/2 teaspoon)
- Contact lens solution (1 tablespoon) - must contain boric acid
- Food coloring (optional)
- Mixing bowl
- Spoon or stick for stirring
Instructions
- Pour the glue into your mixing bowl.
- Add food coloring if you want colored slime. Mix well.
- Add the baking soda and stir until combined.
- Add the contact lens solution and stir vigorously.
- The mixture will start to pull away from the bowl and form slime.
- Knead the slime with your hands for 2-3 minutes until it's smooth.
Tip: If the slime is too sticky, add a little more contact lens solution. If it's too stiff, add a bit more glue.
What's Happening?
Slime is a polymer - a long chain of molecules. The glue contains polyvinyl alcohol (PVA), and the boric acid in the contact lens solution creates cross-links between the PVA molecules.
These cross-links make the slime stretchy and flexible. The slime acts as both a liquid (it flows) and a solid (you can pick it up) - this is called a non-Newtonian fluid!
Safety Notes
- Don't eat the slime!
- Wash hands after playing with slime.
- Store in an airtight container when not in use.