Author: Natalie Voss
Materials needed:
- Elmers Clear (or glitter) PVA School Glue
- Water
- Food coloring, confetti, glitter, etc. to mix in
- Borax
Instructions:
- Mix ½ cup water and ½ cup glue into a bowl and combine completely
- Add food coloring, confetti, glitter etc.
- Add ½ cup warm water to a different bowl and then add 1 teaspoon of borax (20 mule team borax) to the bowl and mix until it’s fully dissolved
- Slowly add 4 tablespoons of borax solution into the glue mixture and stir between each; keep mixing until it’s stuck all together
- Knead the slime
Why this works:
A chemical reaction occurs when you mix all these ingredients together. There are borate ions in the saline solution that form cross links with the PVA (polyvinyl acetate) glue and form the stretchy substance. Usually, glue is just made up of long, repeating, and identical strands or molecules, but when the borate is added these long strands get connected, forming a sort of net of molecules. This changes the liquid glue into a more solid form: slime!
The slime gets cold because it is an endothermic reaction: it borrows energy in the form of heat from its surroundings. Some reactions require energy to connect molecules (the strands getting connected to make the liquid glue into slime in our case) and some break molecules apart and release energy. When energy is released, the outside gets hotter (think of hand warmers) and this is called an exothermic reaction.