Two runny liquids are mixed to produce a substance which can be moulded into a ball but flows when left alone.
- Wood or craft glue (PVA glue)
- Borax (sodium tetraborate)
- Wooden or metal spoon for sitrring
- Container to mix and stir in
Dilute the glue slightly by adding a little water. A 1:1 mixture is usually fine. Add to this a dilute solution of borax. Mix thoroughly and you have a new matrial.
The key component of wood or craft glue is polyvinylalcohol (PVA). The long molecules of PVA have been cross-linked by reaction with the tetraborate. What has formed is like a huge net which holds onto the water that was in both solutions in the solution. It is in fact a tetraborate ester which can be broken down with acid.
If PVA alone is available then food colouring added to the solution makes colourful slime. The solutions are 4%(w/w) PVA and 4%(w/w) borax.
Some experimentation with concentrations may be necessary for the very best results with local ingredients.
If the slime is spilt on clothes or carpets it can prove tricky to clean up. It can be allowed to dry or a little acid will break down the ester and the products can be mopped up with plenty of water.
There are a number of methods to test the properties of the new material and how it varies with concentration of the starting materials. For example, one may measure how quickly a given amount of sample flows through a funnel, or flows between two concentric circles printed on a plastic sheet.
White glue is generally safe. Borax will irritate the skin and can be absorbed through the skin. Once the slime has been made it is safe to handle but always wash hands afterwards.