A plastic is a material that can change its shape, so many things can be made of plastic. There are many types of plastic. Some can be shaped only when they are freshly made; then they become hard afterwards. Others can be changed by heating them up or even by melting them.
Most plastics are man-made; they do not occur in nature. They are often made from oil that comes out of the ground. The process of making plastics is usually quite complicated. Most of the materials that are called plastic are polymers. Polymers are long chains of atoms bonded to one another.
People experimented with plastics based on natural polymers for a very long time. Alexander Parkes, an English inventor (1813-1890), created the earliest form of plastic in 1855. It was hard but flexible and transparent, and he called it “Parkensine.”