Science (from Latin scientia, meaning "knowledge") is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe.
Science has an important part to play in our everyday existence, and there is far too much neglect of science; but its intention is to supplement not to supplant the familiar outlook.
Arthur Eddington, Science and the Unseen World (1929).
Water is essential to life, but every year millions of the chemicals produced together with their reactants and by-products enter the water cycle. Many of these chemicals currently remain unidentified, and the risk posed to human health and the environment cannot be fully determined.