Chemistry is the study of the properties of the materials in the world around us. The chemist looks at and tries to interpret changes in materials, from the apparently simple, such as the burning of hydrogen, to the more complex, such as reactions in the body. At the same time, the chemist may be interested in energy changes, or how fast a reaction proceeds. Another important aspect is working out the structure of materials and identifying their constituents. The chemist employs his or her skills to use both simple and complex analytical techniques to determine the composition of every kind of substance. Research and development of new materials is a most important part of chemistry. These new materials include drugs, plastics, rubbers and detergents to name but a few. These are just some of the things which chemistry involves; look around you and you will see the work of the chemist everywhere.