Science is a systematic and organized approach to understanding the natural world through observation and experimentation. It involves developing and testing hypotheses, analyzing data, and drawing conclusions based on evidence. The main goal of science is to explain and understand the natural world, and to use this knowledge to improve our lives.
Science is based on empirical evidence, meaning that it relies on observations of the natural world and experimental data to support or refute hypotheses. Scientific ideas and theories must be testable and subject to rigorous scrutiny in order to be accepted.
There are many different fields of science, including physics, chemistry, biology, geology, astronomy, and many more. Each of these fields has its own unique methods and techniques for gathering and analyzing data, and each contributes to our understanding of the natural world in different ways.
Science has had a profound impact on human society, leading to countless technological innovations and advancements in fields such as medicine, agriculture, transportation, and communication. Science is an ongoing process, and new discoveries and advances are constantly being made as our understanding of the natural world continues to evolve.

Science can be broadly classified into three categories:
- Natural Sciences: This category includes the fundamental branches of science, such as physics, chemistry, biology, earth science, and astronomy. These branches of science are concerned with studying the natural world and the laws that govern it.
- Social Sciences: This category includes disciplines such as psychology, sociology, economics, anthropology, and political science. These sciences study human behavior and social systems.
- Formal Sciences: This category includes mathematics, computer science, and logic. These sciences are concerned with formal systems, such as numbers, symbols, and algorithms.

The fundamental branches of natural science are:
- Physics: the study of matter, energy, and their interactions. It includes subfields such as mechanics, thermodynamics, electromagnetism, optics, and atomic, molecular, and optical physics, among others.
- Chemistry: the study of the composition, properties, and reactions of matter. It includes subfields such as organic chemistry, inorganic chemistry, physical chemistry, analytical chemistry, biochemistry, and environmental chemistry.
- Biology: the study of living organisms, their structure, function, evolution, and interactions with each other and their environment. It includes subfields such as botany, zoology, microbiology, genetics, and ecology, among others.
- Earth Science: the study of the Earth, its structure, composition, and processes. It includes subfields such as geology, meteorology, oceanography, and paleontology.
- Astronomy: the study of celestial objects and phenomena, such as stars, planets, galaxies, and black holes.
These fundamental branches of natural science are interconnected, and each builds upon the others to deepen our understanding of the natural world. For example, physics provides a foundation for chemistry, which in turn provides a foundation for biology. Earth science and astronomy also draw upon principles from these fundamental branches of natural science to better understand the universe we live in.

The fundamental branches of social sciences are:
- Anthropology: the study of humans, their origins, behavior, and cultural, social, and physical development. Anthropology includes subfields such as cultural anthropology, physical anthropology, and linguistic anthropology.
- Economics: the study of the production, consumption, and distribution of goods and services. Economics includes subfields such as microeconomics, macroeconomics, and international economics.
- Political Science: the study of the government, politics, and public policies of societies. Political science includes subfields such as political theory, comparative politics, and international relations.
- Psychology: the study of the human mind and behavior, including cognitive, emotional, and social processes. Psychology includes subfields such as abnormal psychology, developmental psychology, and social psychology.
- Sociology: the study of human society, including social structure, social interaction, and social change. Sociology includes subfields such as criminology, demography, and medical sociology.
These fundamental branches of social sciences are interconnected, and each builds upon the others to deepen our understanding of human behavior and social systems. For example, anthropology and sociology both examine human societies, but from different perspectives, with anthropology focusing on cultural and biological aspects of humans and sociology on social structures and processes. Economics and political science both explore the ways in which societies make decisions and allocate resources, while psychology provides insights into individual behavior within social contexts.

The fundamental branches of formal sciences are:
- Mathematics: the study of quantity, structure, space, and change. Mathematics includes subfields such as algebra, geometry, calculus, statistics, and numerical analysis.
- Computer Science: the study of the principles and use of computers. Computer science includes subfields such as software engineering, artificial intelligence, database management, and computer graphics.
- Logic: the study of reasoning and argumentation. Logic includes subfields such as mathematical logic and philosophical logic.
These fundamental branches of formal sciences are interconnected, and each builds upon the others to develop new technologies, tools, and methods. Mathematics provides the foundation for computer science, with concepts such as logic, set theory, and algebra forming the basis of programming languages and algorithms. Computer science in turn provides new methods for solving mathematical problems and allows for the development of new mathematical models and tools. Logic is a foundational element of both mathematics and computer science, and is used to develop and validate mathematical proofs and algorithms, as well as to reason about computational systems.