History of the Atom
* Democritus
Democritus had a theory that all matters are composed with tiny unbreakable particles called atom. He tried to break down matters into smallest particles. His model was that the matter would stop splitting in halves when it reaches its smallest matter. He called that an atom. * John Dalton
In 1803, John Dalton proposed a theory. The theory had 4 parts into it. 1. Elements are made of identical atoms. 2. Atoms of different elements are physically different 3. Compounds are formed by a combination of two or more different kinds of atoms. 4. A chemical reaction is arrangement of atoms.
Dalton formed different compounds from its elements. Adding extra of one reactant made no different. He tried variety of different combinations to form a new compound. The ratio that he was combining was inaccurate, but for the time back then, his experiment was closer to the modern technology.
* JJ Thomson
He tested the origin and properties of cathode ray using a cathode ray tube. And his observation was with electricity, a metal plate produces a cathode ray. The model is called plum pudding model. Because it has negative charged particles named electrons inside atom. They can be removed or added to form an iron.
* Loard Ernest Rutherford * Lord Ernest Rutherford came from Nelson New Zealand. In 1911, his observation was the atom should be, if the plum theory was correct, solid pudding, small particles might not pass through the pudding. For experiment, Alpha particles were shot through the gold and beamed out. Almost all alpha particles passed through a thin sheet of gold but some were deflected or bounced back.
* Neil bohr
Neils Bohr came up with a observation that, since + and – charges electrons on the outside should come crashing into the nucleus cancelling both out. His experiment involved studying light coming from atoms that are ‘excited’ by electricity or flame. The light is made of distinct colour liens
Democritus had a theory that all matters are composed with tiny unbreakable particles called atom. He tried to break down matters into smallest particles. His model was that the matter would stop splitting in halves when it reaches its smallest matter. He called that an atom. * John Dalton
In 1803, John Dalton proposed a theory. The theory had 4 parts into it. 1. Elements are made of identical atoms. 2. Atoms of different elements are physically different 3. Compounds are formed by a combination of two or more different kinds of atoms. 4. A chemical reaction is arrangement of atoms.
Dalton formed different compounds from its elements. Adding extra of one reactant made no different. He tried variety of different combinations to form a new compound. The ratio that he was combining was inaccurate, but for the time back then, his experiment was closer to the modern technology.
* JJ Thomson
He tested the origin and properties of cathode ray using a cathode ray tube. And his observation was with electricity, a metal plate produces a cathode ray. The model is called plum pudding model. Because it has negative charged particles named electrons inside atom. They can be removed or added to form an iron.
* Loard Ernest Rutherford * Lord Ernest Rutherford came from Nelson New Zealand. In 1911, his observation was the atom should be, if the plum theory was correct, solid pudding, small particles might not pass through the pudding. For experiment, Alpha particles were shot through the gold and beamed out. Almost all alpha particles passed through a thin sheet of gold but some were deflected or bounced back.
* Neil bohr
Neils Bohr came up with a observation that, since + and – charges electrons on the outside should come crashing into the nucleus cancelling both out. His experiment involved studying light coming from atoms that are ‘excited’ by electricity or flame. The light is made of distinct colour liens
Cited: 1. Democitus. (n.d.). A BRIEF HISTORY OF ATOMIC THEORY DEVELOPMENT. Retrieved September 26, 2010, from http://www.neoam.cc.ok.us/~rjones/Pages/online1014/ September 26, 2010, from New York Times website: http://science.howstuffworks.com/environmental/energy/oil-refining1.htm 3.Helmenstine, A. M. (2010). Ionization Detectors. In How Do Smoke Detectors Work? Retrieved September 26, 2010, from New York Times website: In Nuclear Bombs ... How They Work. Retrieved September 26, 2010, from Worsley School website: http://www.worsleyschool.net/science/files/nuclear/bomb.html