The atomic theory is a theory of the nature of matter. It states that all matter is composed of atoms. The philosophical background of the atomic theory is called atomism. This definition is valid for the matter commonly surrounding us. Strictly speaking it is not valid in plasmas or other particular environments characterized for instance by very large pressure (e.g. neutron stars).
Importance
Arguably, the atomic theory is one of the most important theories in the history of science, with wide-ranging implications for both pure and applied science. The theory is credited to John Dalton, an 18th- and 19th century British chemist.
Modern chemistry (and biochemistry) is based upon the theory that all matter is made up of atoms of different elements which cannot be transmuted by chemical means. In turn, chemistry has allowed for the development of the pharmaceutical industry, the petrochemical industry, and many others.
Much of thermodynamics is understandable in terms of kinetic theory, whereby gases are considered to be made up of either atoms or molecules, behaving in accordance with Newton's laws of motion. This was, in turn, a large driving force behind the industrial revolution.
Indeed, many macroscopic properties of matter are best understood in terms of atoms. Other examples include friction, material science and semiconductor theory. The latter is particularly important, as it is the foundation of electronics.
History
The existence of atoms was proposed in the East by 2nd century BCE Indian philosopher Kanada and in the West by 5th century BCE Greek philosophers such as Democritus, Leucippus, and the Epicureans. Without any way to test the hypothesis, the concept disappeared until it was revived by Rudjer Boscovich in the 18th century, and after that applied to chemistry by John Dalton. Boscovich based his theory on classical mechanics and published it in 1758. The theory was further developed by Amedeo Avogadro and developers of the kinetic theory of gases such as James Clerk Maxwell and Ludwig Boltzmann.
In the late 19th century, a movement led by Ernst Mach, Wilhelm Ostwald, and Karl Pearson rejected the atomic theory on epistemological grounds. The dispute was not finally settled until Jean Perrin's experimental investigation of Einstein's mathematical theory of Brownian motion in the early 20th century.
See also
- Timeline of quantum mechanics, molecular physics, atomic physics, nuclear physics, and particle physics
- Timeline of thermodynamics, statistical mechanics, and random processes
- Timeline of chemical element discoveryar:نظرية ذرية
he:התורה האטומית
ko:원자론
nn:Atomteori
zh:原子論
Categories: Atomic physics | Chemistry theories | Foundational quantum physics | Albert Einstein
