photochemistry

Photochemistry is the study of how light interacts with chemicals. In photochemistry, the light is used to change the way the chemicals look or act. For example, it can be used to start a reaction in a chemical, like when a plant uses sunlight to turn carbon dioxide and water into sugar, a process called photosynthesis. Photochemistry is used in lots of everyday things like tanning lotion, sunscreen, photography paper and clothing dyes.