There are two kinds of rubber: natural rubber and rubber made from oil.
Natural rubber is made from the sap of the rubber tree which grows in very warm parts of the world. The sap is called latex and it is collected by making a long cut through the bark. The sap runs down the cut and is collected in a pot which is strapped to the tree trunk. Latex is a white, watery liquid. When the water is removed by drying and then running between rollers, sheets of rubber are formed.
Some chemicals are made into rubber-like materials. This kind of rubber is called synthetic rubber. It is a manufactured material.
Soft rubber, called crepe rubber, is used for making the soles of shoes and sandals. Its elastic properties make walking on pavements and other hard surfaces more comfortable than leather soles which are not elastic.
Most rubber is made harder and stronger by mixing chemicals with it. This process is called vulcanization. The rubber still has some elastic properties and so it can be used to make such things as tennis balls and golf balls. Synthetic rubber is also used to make 'elastic' bands and to make 'rubber' gloves. Synthetic rubber is also used for making Wellington boots.
Rubber may be made into a foam by blowing air through liquid rubber. This type of rubber is used to make furniture and cushions.