Natural science

In science, natural science is the rational study of the universe via rules or laws of natural order. The term natural science is also used to distinguish those fields that use the scientific method to study nature from the social sciences, which use the scientific method to study human behavior, and from the formal sciences, such as mathematics and logic, which use a different methodology.

Overview
Natural sciences form the basis for the applied sciences. Together, the natural and applied sciences are distinguished from the social sciences on the one hand, and from the humanities, theology and the arts on the other. Mathematics, statistics and computer science are not considered natural sciences, but provide many tools and frameworks used within the natural sciences.

Alongside this traditional usage, the phrase natural sciences is also sometimes used more narrowly to refer to its everyday usage, that is, related to natural history. In this sense "natural sciences" may refer to the biological sciences and perhaps also the earth sciences, as distinguished from the physical sciences, including astronomy, physics, and chemistry.

Within the natural sciences, the term hard science is sometimes used to describe those sub-fields that rely on experimental, quantifiable data or the scientific method and focus on accuracy and objectivity. These usually include physics, chemistry and many of the sub-fields of biology. By contrast, soft science is often used to describe the scientific fields that are more reliant on qualitiative research, including the social sciences.

See Category:Science for articles about the individual Natural sciences

A narrower view
According to a famous 1923 textbook Thermodynamics – and the Free Energy of Chemical Substances by the American chemist Gilbert Lewis and the American physical chemist Merle Randall, the natural sciences contain three great branches:

History
Prior to the 17th century, the objective study of nature was known as natural philosophy. Over the next two centuries, however, a philosophical interpretation of nature was gradually replaced by a scientific approach using inductive methodology. The works of Sir Francis Bacon popularized this approach, thereby helping to forge the scientific revolution.

By the 19th century the study of science had come into the purview of professionals and institutions, and in so doing it gradually acquired the more modern name of natural science. The term scientist was coined by William Whewell in an 1834 review of Mary Somerville's On the Connexion of the Sciences. However the word did not enter general use until nearly the end of the same century.

Astronomy
This discipline is the science of celestial objects and phenomena that originate outside the Earth's atmosphere. It is concerned with the evolution, physics, chemistry, meteorology, and motion of celestial objects, as well as the formation and development of the universe. Astronomy includes the examination, study and modeling of stars, planets, comets, galaxies and the cosmos. Most of the information used by astronomers is gathered by remote observation, although some laboratory reproduction of celestial phenomenon has been performed (such as the molecular chemisty of the interstellar medium.)

While the origins of the study of celestial features and phenomenon can be traced back to antiquity, the scientific methodology of this field began to develop in the middle of the seventeenth century. A key factor was Galileo's introduction of the telescope to examine the night sky in more detail. The mathematical treatment of astronomy began with Newton's development of celestial mechanics and the laws of gravitation, although it was triggered by earlier work of astronomers such as Kepler. By the nineteenth century, astronomy had developed into a formal science with the introduction of instruments such as the spectroscope and photography, along with much improved telescopes and the creation of professional observatories.



Biology
This field encompasses a set of disciplines that examines phenomena related to living organisms. The scale of study can range from sub-component biophysics up to complex ecologies. Biology is concerned with the characteristics, classification and behaviors of organisms, as well as how species were formed and their interactions with each other and the natural environment.

The biological fields of botany, zoology, and medicine date back to early periods of civilization, while microbiology was introduced in the 17th century with the invention of the microscope. However it was not until the 19th century that biology became a unified science; once scientists discovered commonalities between all living things it was decided they were best studied as a whole. Some key developments in the science of biology were the discovery of genetics; Darwin's theory of evolution through natural selection; the germ theory of disease and the application of the techniques of chemistry and physics at the level of the cell or organic molecule.

Modern Biology is divided into sub-disciplines by the type of organism and by the scale being studied. Molecular biology is the study of the fundamental chemistry of life, while cellular biology is the examination of the cell; the basic building block of all life. At a higher level, Physiology looks at the internal structure of organism, while ecology looks at how various organisms interrelate.

Chemistry
Constituting the scientific study of matter at the atomic and molecular scale, chemistry deals primarily with collections of atoms, such as gases, molecules, crystals, and metals. The composition, statistical properties, transformations and reactions of these materials are studied. Chemistry also involves understanding the properties and interactions of individual atoms for use in larger-scale applications. Most chemical processes can be studied directly in a laboratory, using a series of (often well-tested) techniques for manipulating materials, as well as an understanding of the underlying processes.

Earth science
The study of Earth, including geology, geophysics, hydrology, meteorology, physical geography, oceanography, and soil science.

Physics
The study of the fundamental constituents of the universe, the forces and interactions they exert on one another, and the results produced by these forces.

Cross-disciplines
The distinctions between the natural science disciplines is not always sharp, and they share a number of cross-discipline fields. Physics plays a significant role in the other natural sciences, as represented by astrophysics, geophysics, physical chemistry and biophysics. Likewise chemistry is represented by such fields as biochemistry and astrochemistry.