-
Jan 1, 1000
Aristotle
He believed you could figure out and understand things by just thinking sbout them. He also thought that everything was made out of a combination of four elements: earth, fire, water, and air. His idea was that a mass of incomprehensible size was everywhere. He called this "hyle." There were no seperate "particles" for each material. -
Jan 1, 1000
Democritus
"by convention bitter, by convention sweet, but in reality atoms and void" To Democritus, atoms did not make up just everyday objects, but influenced his thoughts on sight, senses, and soul. -
Alchemists- Isaac Newton
He belived that there are tiny pieces of mass "swimming" everywhere. He began to understand that atoms or particles move and are not stationary. -
Antoine Lavoisier
He came up with the Law of Conversion by using his favorite experiment where he turned HgO into Hg+O. The law states that cannot be destroyed or made. He started the conversion on what an atom was exactly. -
John Dalton
He proposed an "atomic theory" with spherical solid atoms. These were based upon measurable properties of mass. -
Sir William Crookes
He discovered that cathode rays had certain properties. Some of these properties were to travel a straight line, cause glass to fluoresce, and impact a negative charge to objects they strike. -
M. K. Roentgen
He was trying to reproduce a fluorescent effect. The filament inside of the vacuum tube produce a steam of electrons which is well known as a cathode ray had excited the atoms of an aluminnium to produce x-rays, which in return excited the atoms of the barium. -
Becquerel
While studying the effect of x-rays on photographic film, he discovered some chemicals spontaneously decompose and give off very penetrating rays. -
Marie Sklodowska Curie
He studied thorium and uranium and called their decay process "radioactivity." she and her husband Peirre also discovered the radioactive elements radium and polonium. -
Max Planck
The propesed that energy is radiated in very minute and discrete quantitized amounts packets, to explain the colors of hot glowing matter. This was thought of rather than continuos unbroken wave. -
Hans Geiger
He introduced the first detector of individual alpha particles. He introduced it in July 1928 of the Geiger-Müller counter marked the introduction of modern electrical devices into radiation research. -
Robert Millikan
He measured the change on an electron. He used an experiment where he used the atomizer from a perfume bottle and was used to spray water or oil droplets into a sample chamber. -
Ernest Rutherford
he probed the atoms in a piece of thin gold foil, by using alpha particles as atomic bullets.He established that the nucleus was very dense, very small, and positively charged. -
Niels Bohr
He came up with an explanation for atomic structures that disagreed with the periodic table.the atomic model he made had atoms built up of successive orbital shells of elements. -
Erwin Schrodinger
He viewed electrons as continuous clouds. He also introduced "wave mechanics" as a mathamatical model of the atom. -
Chadwick
Discovered a neutral atom particle with mass close to a proton, by using alpha particles. In a result he discovered the neutron. -
Lise Meither
She created experiments verifying that heavy elements capture neutronsand form unstable products which undergo fission. By continuing the fission chain reaction, this process ejects more neutrons. -
Glen T. Seaborg
He synthesized six transuranium elements. He also suggested a change in the layout of the periodic table.
