Most plastics are made from oil. Oil is a long-chain hydrocarbon, meaning that it is composed of long chains of carbon molecules. These long chains of carbon molecules give plastic its characteristic strength and flexibility.
Plastic is full of long, organic molecules, called polymers. While most plastics are made from oil or similar petrochemicals, they can be formed from just about any organic polymer available. Different types of plastics are suited for different types of tasks, and the manner in which they are made varies from one type to another. Some plastics are designed to be transparent and carry drinking water, while others are designed to be opaque and carry dangerous chemicals.
In addition to being easy to work with and strong, plastics are benign materials that do not react with many chemicals. This is why plastics can be used to carry many different types of substances. For example, alcohol, gasoline and some acids can be contained safely in plastic containers. While this is beneficial to those who produce plastics or use it for commercial purposes, it also means that plastic does not break down quickly. Plastics may linger in landfills for centuries before microscopic organisms and chemicals are able to degrade them.