Chemistry is a branch of natural science that deals principally with the properties of substances, the changes they undergo, and the natural laws that describe these changes. The study of chemistry spans the range from qualitative in focus to quantitative. The more qualitative chemist might work on synthesizing a new compound used in medicine, for example, while the more quantitative work can seem much like physics applied to the microscopic level of atoms and molecules.
Chemicals are everywhere and are everything. Anything you can touch or smell or see contains one or more chemicals. Many occur naturally but some are man made. Chemists discover naturally occurring chemicals and also make new ones never seen before. Chemists study the properties of the natural and man made chemicals. This information is used to understand how some chemicals may be modified to make them more useful and they develop the methods to make the modifications. Chemists seek to study the natural world but also seek to improve it by modification on a molecular level. Because everything is a chemical, chemistry is one of the foundations of modern industrial economies. Advancements in the field of chemistry have brought about major improvements in our world. Improvements range from new medicines that cure disease, to new materials that make us safer and stronger, to new sources of energy that enable new activities.