edward.nigrelli.atomichistory.fall.2009

=__**450-PRIOR**__=



460 B.C.-370 B.C.
Believed that atoms were "infinite in numbers imperceptible because of the minuteness of their size, they move about in empty space and when joined form objects". Democitus stated that all changes in the world were a direct result of changes in atoms. He also believed that everything was made up of atoms.



**Leucippus 440BC**
He is the man who taught Democritus about the atom. He believed everything consisted of two elements, solid and volid. He believe there was infinite atoms.

Aristotle 384-322BC


Aristotle was born in Greece. He was sent to Athens to study at Plato's Academy. He believed that all his surroundings were made up of four elements: water earth fire and water.

=__**1700-1800**__=

__Antoine Lavoisier__


Stated the first version of the law of conservation of mass. He also discovered that even though objects can change their shape and size, their amount of matter remains constant. He also discovered that air was a mixture of oxygen and nitrogen, mostly nitrogen.

James Bradley


In 1728 Bradley discovered the aberration of light. This provided a good basis for the belief that the Earth revolved around the Sun.

1733-1804


He claimed to have discovered oxygen because he was the first to get it in its gaseous state. He created soda water and also discovered some more gases. He also discovered alot in the field of electricity and contributed to the clergy in England as well. He was also a political figure throughout England.

1783-1850


He was and English inventor. He came up with the first electromagnets. He also invented the first English practical motor. In 1828 he put into practice Ampere's idea of a solenoid.

=__**1800-1875**__=

John Dalton
1766-1844



HIs atomic theory consisted of four different parts and they were 1)all matter is made up of atoms that are inseperable and indestructable. 2)all atoms in an element have the same mass 3)compounds can be formed when two or more kinds of atoms join 4)a chemical reaction is a rearrangement of atoms.

Demitri Mendeleev
1834-1907



Mendeleev was the creator of the first variation of the periodic table of elements. With his table he could predict properties of elements that had not been discovered yet. Alot of chemists of his time dismissed him for thinking that there were more elements et to be discovered (but i guess he showed them).

=__**1875-1900**__=

William C. Roentgen
1845-1923



=== he was experimenting with electric current flow in a partially evacuated glass tube and observed that a nearby piece of barium gave off light when the tube was in operation. He theorized that some unknown radiation was causing the fluorescent light. this was the beginning of the x-ray. ===

1867-1933
 1867-1934 Curie studied uranium radiations. Marie Curie was the first to use the term radioactive to describe elements that give off radiations as their nuclei break down. Pierre Curie ended his own work on magnetism to join his wife's research, and the Curies announced their discovery of two new elements radium and polonium. Marie Curie was the first female recipient of the Nobel Prize.
 * [[image:marie.jpg width="299" height="355"]] ||
 * Marie Curie ||

1856-1940

 * [[image:jj_thompson_400px.jpg width="254" height="280" caption="Joseph John Thomson"]] ||

He discovered the electron in a series of experiments designed to study the nature of electric discharge in a high-vacuum cathode-ray tube. In 1904 he suggested a model of the atom as a sphere of positive matter in which electrons are positioned by electrostatic forces. It is known as the plum pudding model.
 * \[[image:plum_pudding.jpg width="257" height="257"]] ||

__ ** 1900-1915 ** __

1865-1962

 * [[image:NielsBohr1.jpg width="264" height="363" caption="Niels Bohr 1865-1962"]] ||



In 1913, Bohr published a theory about the structure of the atom based on an earlier theory of Rutherford's. Rutherford had shown that the atom consisted of a positively charged nucleus, with negatively charged electrons in orbit around it. Bohr expanded upon this theory by proposing that electrons travel only in certain larger orbits. He said that some orbits were larger than other ones and they could hold more electrons.


 * ==Robert Millikan==
 * ==Robert Millikan==

[[image:millikan.jpg width="189" height="272"]]
||

In 1909 Millikan began a series of experiments to determine the electric charge carried by a single electron. He began by measuring the course of charged water droplets in an electrical field. He obtained precise results in 1910 with his famous oil-drop experiment in which he replaced water with oil.

1871-1937

 * [[image:Ernest_Rutherford.JPG width="273" height="369" caption="Ernest Rutherford"]] ||
 * Ernest Rutherford ||



He displayed that radioactivity was a spontaneous disintegration of atoms. He came up with the Rutherford model which had electrons orbiting the nucleus. he was the first person to transmute one element into another when he did it to nitrogen into oxygen.

__ 1915-1950  __

1891-1974
===Chadwick discovered the nuetron, before then nobody knew of this subatomic particles existence. His work helped alot in the creation of the atomic bomb. ===
 * [[image:James_Chadwick_1.jpg width="202" height="275" caption="James Chedwick"]] ||

1901-1976

 * [[image:heisenberg.jpg width="240" height="272"]] ||
 * [[image:heisenberg.jpg width="240" height="272"]] ||

He made alot of contributions to quantum mechanics. He is best known for his work with the uncertainty principle of quantum theory. He used gamma rays to try and measure certain things about an electron. He found you could find its momentum or position. He was German and worked on the German atomic bomb.


 * ==Erwin Schrodinger==

1887-1961
||

Shrodinger came up (obviously) with the Schrodinger equation. He was a theoretical physicist. he deccribed the movement of atoms and electrons as waves with mathematics.




 * Sources

http://www.bookrags.com/biography/democritus/ http://www.docstoc.com/docs/4580677/aristotle-atomic-theory

http://en.wikipedia.org/wiki/Antoine_Lavoisier http://en.wikipedia.org/wiki/Joseph_Priestley http://en.wikipedia.org/wiki/James_Bradley_%28author%29 http://en.wikipedia.org/wiki/John_Dalton

http://en.wikipedia.org/wiki/Mendeleev http://en.wikipedia.org/wiki/Marie_Curie

http://en.wikipedia.org/wiki/Roentegen

http://en.wikipedia.org/wiki/John_Thomson

http://en.wikipedia.org/wiki/NIels_Bohr

http://en.wikipedia.org/wiki/Ernest_Rutherford

http://en.wikipedia.org/wiki/James_Chadwick

http://en.wikipedia.org/wiki/Werner_Heisenberg

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