Smile slime

Procedure

• Add 20 g of white glue to a beaker.
• Add 2 drops of food coloring and stir well.
• Next, gradually add a little of the borax solution to the white glue while stirring continuously with the glass stirring rod until we obtain the consistency of slime.
• Separate the viscous mass and observe its properties.
• Try to make a ball, what happens if we bounce it?
• Take a little of this mass and immerse it in vinegar. Observe what happens.
• Let the ball you made dry for a few days and then observe if the properties have changed.

Theoretical explanation

The white glue we used contains polyvinyl alcohol, which is a polymer with a very long chain. When we add the sodium tetraborate, its molecules form bonds that act as bridges between two polyvinyl alcohol chains, creating a cross-linked polymer with properties different from the initial polymer.

Vinegar is an acidic substance that causes the bonds between the two polymer chains of polyvinyl alcohol and borax to break. As a result, the “new polymer” loses viscosity and its properties resemble those of white glue.