Natural rubber is a polymer made of isoprene monomers. It is in fact a terpene – a polyterpene.
In alkaline conditions, the latex remains in suspension but when the solution is acidified (with lemon juice or vinager for instance) it will solidify to form rubber as we know it.
Here are three short experiments to make: a rubber ball, a rubber band and some foam rubber.
Make a rubber ball
Make a rubber band
Make some foam rubber
Latex rubber risk assessment