Ok, so it’s no where near Halloween yet, but this stuff is so much fun, so I couldn’t wait.
What you’ll need:
- Water
- PVA glue
- Borax powder (chemical name: sodium tetraborate)
- Food colouring
- An old tub and stirring implements
What to do:
Simply mix an equal volume of water to PVA glue (ie if you have 250ml of PVA glue, then you mix it with 250ml water). Add the food colouring and mix thoroughly.
Next, mix half a teaspoon of Borax with about ¾ of the volume of water used before – the borax won’t dissolve in the cold water, but just make sure it’s mixed thoroughly.
Finally, combine the two mixtures together slowly, once it starts forming a glob you can take this out and knead it… and voila! Slime!
So how does it work? Basically, PVA glue is made up of a bunch of single units all chained together, and though a thick, or viscous, liquid, these chains are generally able to slide over and past each other with little problem.
The borax (sodium tetraborate) acts to make links between the chains – this results in a thicker substance as all the PVA units are linked together in to a big mesh that doesn’t allow water around the molecules so much. This process is called crosslinking. But is it a solid, or a liquid? The technical term is a non-newtonian liquid. This means that when a force is acted upon it it will act like a solid and resist that force, and the more force you apply, the more solid-like it acts.
A Little Adivce
Borax (Sodium Tetraborate) can be an irritant, so please supervise carefully any children whilst doing this and DO NOT eat the glue, borax or final slime! You can handle the slime, but be sure to wash it off, and it should come off in warm, soapy water if you get it on your clothes. The slime can be stored in a sealed container for a couple of weeks int the fridge.