Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe.
Modern science is typically divided into three major branches:
natural sciences (e.g., biology, chemistry, and physics), which study the physical world;
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 study formal systems, governed by axioms and rules.
There is disagreement whether the formal sciences are science disciplines, because they do not rely on empirical evidence. Applied sciences are disciplines that use scientific knowledge for practical purposes, such as in engineering and medicine.
New knowledge in science is advanced by research from scientists who are motivated by curiosity about the world and a desire to solve problems. Contemporary scientific research is highly collaborative and is usually done by teams in academic and research institutions, government agencies, and companies. The practical impact of their work has led to the emergence of science policies that seek to influence the scientific enterprise by prioritizing the ethical and moral development of commercial products, armaments, health care, public infrastructure, and environmental protection.