Science is the study of the nature and behaviour of natural things and the knowledge that we obtain about them.
Modern science is typically divided into three major branches] that consist of the natural sciences (e.g., biology, chemistry, and physics), which study nature in the broadest sense; the social sciences (e.g., economics, psychology, and sociology), which study individuals and societies, and the formal sciences (e.g., logic, mathematics, and theoretical computer science), which deal with symbols governed by rules. There is disagreement, however, on whether the formal sciences actually constitute a science as they do not rely on empirical evidence. Disciplines that use existing scientific knowledge for practical purposes, such as engineering and medicine, are described as applied sciences.