To make them bounce.
The type of rubber used to make balls is called polybutadiene rubber.
no there made of leather on the outside but with some rubber in the inside then just filled with air.
Rubber balls make good cat toys. Most cats love to chase them around.
list of items made of rubber
re-enforced rubber and a slim layer of some bouncy material American dodgeballs are made of rubber and pumped with air. where I'm from (the UK) we use foam balls with a hard plastic layer on the outside.
Rub my metal balls or rubber balls.
Because rubber is bouncy!!!! and bouncy balls are made out of rubber.
uses of a rubber tree 1.Prehistoric uses 2.Manufacturing 3.Textile Applications
The centers of tennis balls are rubber and rubber hardens with age.
The rubber balls used in 40mm rubber ball munitions for the Marines typically have a caliber of 40mm. These projectiles are designed for use in launchers that fire 40mm rounds and are intended for crowd control and non-lethal applications. The rubber balls are engineered to minimize injury while still being effective for their intended purpose.
Most golf ball are made of plastic inside and rubber outside.
Latex is used in the manufacturing of most rubber balls that are produced. However, it is possible to purchase rubber balls which are made of a vinyl material for people with latex allergies.