You will need:
Finished bouncy polymer ball!
Australian Curriculum Links (ACARA)
Natural and processed materials have a range of physical properties; these properties can influence their use (ACSSU074).
CW4 - In a chemical change, new substances are formed, which may have specific properties related to their uses in everyday life. Chemical change involves substances reacting to form new substances (ACSSU225)
CW3 - Chemical reactions involve rearranging atoms to form new substances; during a chemical reaction mass is not created or destroyed (ACSSU178)
CW4 - Different types of chemical reactions are used to produce a range of products and can occur at different rates and involve energy transfer (ACSSU187).
The PVA in PVA Glue stands for Poly-Vinyl Alcohol. It’s a special sort of chemical called a polymer. The “Poly” part of PVA means many, because PVA is made of lots and lots of units added together into big long chains. Usually they chains slip and slide past each other, and we get a flowing liquid.
Borax is a chemical that we usually use for cleaning, but it has another interesting property. When it’s mixed with Poly-Vinyl Alcohol, it grabs those long chains of polymer, and links them together (leaving water behind as a by-product). Now, the properties of the PVA change: instead of slip sliding past each other, the PVA-borax mixture stretches and clumps together into a kind of slime.
By adding cornflour to the PVA and Borax mixture you now have a material which becomes harder when you give it more pressure... a non-Newtonian solid combined with an elastic slime! This means that when you bounce the ball it can then transfer the forces back into the floor more easily and the ball bounces easily. You can also make cornflour slime which takes advantage of non-Newtonian solid properties.