Chemical engineering is a branch of engineering dealing with chemistry that came to existence in the early 20th century. Before this time, chemical plants were designed by chemists, who were trained to work on a small scale only. Chemical engineering combines the jobs of a chemist and that of industrial engineer. This makes factories more efficient and chemicals much cheaper. Chemical engineering uses physics (the science of moving objects and forces), chemistry (the science of substances), and mathematics. There are many different types of jobs for people with degrees in chemical engineering.