How are Plastics Made?

Have a look around you.
How many things can you see made from plastics?
In the modern world, different kinds of plastics are everywhere.
Some people even have pieces of plastic in their bodies, such as valves fitted to their hearts, or joints in knees and hips.
Most plastics are synthetic, which means they are not natural, but have been invented by scientists.
Polyvinyl chloride, or PVC for short, is used to make toys, pipes, and raincoats.
Another type of plastic, polytetrafluoroethylene, PTFE, is used to coat the inside of nonstick saucepans. Many pens are made from a plastic called polystyrene.

How is plastic made from oil?

Most plastics are made from chemicals taken from crude oil.
In an oil refinery, oil is separated into several different substances.
One of them is a hydrocarbon called ethylene. 
The molecules of a hydrocarbon combine into long chains called polymers. 
A special chemical called a catalyst is needed to make this happen.
When scientists combine ethylene molecules, they make a polymer called polyethylene. 
Polyethylene is a plastic which is used to make bottles and containers.
By adding different catalysts to different hydrocarbons, other kinds of plastics can be made.