gatorshelton

Examine the history of the development of the atom. We have already discussed the
major players in the development of the atom. Pick out at least 8 major players who
helped aid in the development of the concept of the atom. Then explain each
experiment in a concise explanation. Then explain how each one aided in the
development of the next or how their concept assisted in the further development of the current quantum model of the atom.


Democritus:The theory of Democritus and Leucippus held that everything is composed of "atoms", which are physically, but not geometrically, indivisible; that between atoms lies empty space; that atoms are indestructible; have always been, and always will be, in motion; that there are an infinite number of atoms, and kinds of atoms, which differ in shape, and size. Of the mass of atoms, Democritus said "The more any indivisible exceeds, the heavier it is." But their exact position on weight of atoms is disputed.

Issac Newton: Newton laid the foundation for differential and integral calculus. His work on optics and gravitation make him one of the greatest scientists the world has known. Newton's greatest achievement was his work in physics and celestial mechanics, which culminated in the theory of universal gravitation. By 1666 Newton had early versions of his three laws of motion. He had also discovered the law giving the centrifugal force on a body moving uniformly in a circular path. However he did not have a correct understanding of the mechanics of circular motion.



john dalton:John Dalton developed the first useful atomic theory of matter around 1803. In the course of his studies on meteorology, Dalton concluded that evaporated water exists in air as an independent gas. He wondered how water and air could occupy the same space at the same time, when obviously solid bodies can't. If the water and air were composed of discrete particles, Dalton reasoned, evaporation might be viewed as a mixing of water particles with air particles. He performed a series of experiments on mixtures of gases to determine what effect properties of the individual gases had on the properties of the mixture as a whole. While trying to explain the results of those experiments, Dalton developed the hypothesis that the sizes of the particles making up different gases must be different.

J.J. Thomson: J J Thomson experimented on cathode rays. In Britain, physicists had argued these rays were particles, but German physicists disagreed, thinking they were a type of electromagnetic radiation. Thomson showed that cathode rays were particles with a negative electric charge and much smaller than an atom. He also thought all atoms contained them. These particles were later named electrons.



micheal faraday:Faraday's introduction of the concept of lines of force was rejected by most of the mathematical physicists of Europe, since they assumed that electric charges attract and repel one another, by action at a distance, making such lines unnecessary. Faraday had demonstrated the phenomenon of electromagnetism in a series of experiments, however. This experimental necessity probably led the physicist James Clerk Maxwell to accept the concept of lines of force and put Faraday's ideas into mathematical form, thus giving birth to modern field theory.



Dmitri Mendeleev: Arranged elements into 7 groups with similar properties. He discovered that the properties of elements "were periodic functions of the their atomic weights". This became known as the Periodic Law.


albert einstein:Einstein's contributions to physics began in 1905 with three major results: the explanation of Brownian motion in terms of molecules; the explanation of the photoelectric effect in terms of the quantum; and the special theory of relativity that links time to space and energy to matter. From 1907 to 1915 Einstein developed general relativity, a theory of gravity more accurate than Newton's; it became the basis of theoretical cosmology. In failed efforts in the 1930s to refute the interpretation of quantum theory in terms of probability, Einstein contributed to the theoretical basis for what is sometimes called teleportation of photons (which Einstein called "spooky action at a distance"). His last major effort was an attempt to unify electromagnetism and gravity into a single unified field theory, still an active problem of physics.

niels bohr:Niels Bohr was a Danish physicist who made fundamental contributions to understanding atomic structure and quantum mechanics, for which he received the Nobel Prize in Physics in 1922. He was also part of the team of physicists working on the Manhattan Project. Bohr married Margrethe Nørlund in 1912, and one of their sons, Aage Niels Bohr, grew up to be an important physicist, who like his father received the Nobel prize, in 1975. Bohr is widely considered to be the one of the greatest physicists of the 20th century.