Science (from Latin: scientia, meaning “knowledge”) is a systematic enterprise of gathering knowledge about the world and organizing and condensing that knowledge into testable laws and theories. As knowledge has increased, some methods have proved more reliable than others, and today the scientific method is the standard for science. It includes the use of careful observation, experiment, measurement, mathematics, and replication — to be considered a science, a body of knowledge must stand up to repeated testing by independent observers. The use of the scientific method to make new discoveries is called scientific research, and the people who carry out this research are called scientists. This article focuses on science in the more restricted sense, what is sometimes called experimental science. Applied science, or engineering, is the practical application of scientific knowledge.
A scientific hypothesis is an educated guess about the nature of the universe, a scientific theory is a hypothesis which has been confirmed by repeated observation and measurement. Scientific theories are usually given mathematical form, and are always subject to refutation if future experiments contradict them.
In the modern world, scientific research is a major activity in all developed nations, and scientists are expected to publish their discoveries in refereed journals, scientific periodicals where referees check the facts in an article before it is published. Even after publication, new scientific ideas are not generally accepted until the work has been replicated.