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Democritus and the Atom
Democritus was the first to develop the idea of the atom. He wondered what would happen if he broke something in half and kept on doing that until he couldn't do it anymore. His idea made him think about what that smallest piece of something was and he called it the atom. -
Jan 1, 600
Thales and Electricity
Electricity was thought of before atoms were. Thales found out about it by rubbing a piece of amber with fur. It collected small pieces of dust. -
Antoine Lavoisier and Oxygen
Antonie Laviosier found the element of oxygen and made the Law of Conservation. -
John Dalton and Evidence of the Atom
John Dalton found evidence of the atom when he conducted experiments on different kinds of gases. He found from his research that everything is made from atoms and that the atom of a element and an atom of a different element have different atomic weights. Atoms of different or the same element also combine to make simple whole-number ratios that are chemical compounds. -
Wilhelm Roentgen and X-Rays
He discovered X-rays but didn't know how they were made. -
Henri Becquerel and Gamma Rays
Henri Becquerel found out that uranium emmited certain rays that were similar to the X-rays that Wilhelm found. He found that the radiation did not depend on an external material. Instead it came directly from the uranium. -
J. J. Thomson and the Electron
Scientists from this time have said that the main fundamental unit is the size of a hydrogen atom. J. J. Thomson was the first to suggest that the unit was actually 1,000 times smaller than any atom. He discovered this by experimenting with cathode rays and finding its properties. His experiments showed that cathode rays are 1,000 times lighter than hydrogen atoms and that their mass is always the same no matter what atom they are in. -
Marie Curie and Radioactivity
Based off of Henri Besquerel's and Wilhelm Roentgen's experiments, she looked into it as a possible field of research. After fifteen years later, Marie's husband, Pierre Curie, and his brother made the first electrometer. Using the electrometer Marie found that there was electricity in the air around the uranium tested. -
Albert Einstein and Light Absorption
Albert wrote a paper about how when a quanta (light particle) hits an atom, that atom loses an electon or a proton. -
Robert Millikan and the Mass/Charge of the Electron
J. J. Thomson had already found the charge:mass ratio of the electron, but the actual charge and mass were still unknown. If one of these values were found then the other could be found using the ratio. Millikan and one of his soon-to-be graduates used the oil-drop experiment to measure the charge of the electron. -
Paul Dirac and Antimatter
Paul Dirac was the one that created the modern theory of the antiatom. He realized that his version of the Schrödinger wave equation for electrons showed that there could be antielectrons. -
Ernest Rutherford and the Nucleus
Actually a student of his found out about the subatomic particles, but it was under Rutherford's supervision. There was an element named after him though called rutherfordium(104) in 1997. -
Apologies about Dates
I could not get BC dates so the time is messed up.
