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Aristotle
Around the year 340 BCE, well known Greek philosper Aristolte describes his theory of matter. He defines matter as made up of four basic elements : Fire, that which is hot, Water that which was cool, Air that which was light, and Earth that which was heavy. Although much time has passed, Aristotle's theory has since been proven completly false. The main contribution that lives on from Aristotle is his idea that things are made up of elements. The greatest example is our modern periodic table. -
John Dalton
English meteorologist and chemist John Dalton's contribution to the structure of the atom was formulated back in 1808. His theory on the atom suggested that all matter was composed of an indivisible and indestructible building block. He also believed that all atoms of one element are identical, ans that those elements differ in size and mass. Although this theory has been corrected over the years, Dalton's main contribution was that atomic mass units are recognized in Daltons. -
J.J Thomson
In 1897, British scientist J.J. Thomson's best know for his discorvery of the electron. Using a cathode-ray tube is a series of experiments, thomson observed a deflection of the light rays as evidence of "bodies much smaller than atoms". "In 1904 Thomson suggested a model of the atom as a sphere of positive matter in which electrons are positioned by electrostatic forces."He was also known for his "plum pudding model, as the pudding represented positve matter, and the plums represented negative. -
Albert Einstein
Widely known scientist Albert Einstein contributed to the atomic theory at the age of ripe old age of 26 years old. In 1905, the young Einstein created a mathematical method on how to calculatethe size of atoms and molecules by observing sugar molecules disolving in water. In which, "he measured the diameter of the sugar sugar molecule and Avogadro’s number (the number of molecules per unit volume under standard conditions) from the known viscosity of the liquid and the diffusion rate." -
Ernest Rutherford
Student of J.J. Thomson, Rutherford's theory on describing the atom was that it had a central positive nucleus, surrounded by negative orbiting electrons. The way that he was able to conclude this theory was due to his famous "Gold Foil" experiment.To sum up his trials, the gold foil exeriment consisted of "The firing of radioactive particles through minutely thin metal foils (notably gold) and detecting them using screens coated with zinc sulfide (a scintillator)."
