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Period: 460 BCE to 370 BCE
Democritus
From: Greece
Hypothesized Atoms based on the world’s physical phenomena changing. Used void method to prove his logic. Was a well-known philosopher.
https://www.britannica.com/biography/Democritus -
Period: to
Antoine Lavoisier
From: France
Made the first extensive list of elements, discovered and predicted a few elements. Most of his discoveries were from research on water and air. Was executed by guillotine when charged with stealing from the French Treasury.
https://www.famousscientists.org/antoine-lavoisier/ -
Period: to
John Dalton
From: England
Created an accurate model of what an atom should look like (Dalton's Atomic Model). Used the Law of Multiple Proportions to base the model off of. Taught mathematics in a college. -
Period: to
J.J. Thomson
From: England
Discovered the electron by using the weight of cathode rays to prove that there are matters that way far less than that of hydrogen. Knighted in 1908 by King Edward VII -
Period: to
Max Planck
From: Germany
Discovered Quanta energy (wavelike energy) named Planck's constant. When he heated a black subject electromagnetic radiation came out in waves. The quantum theory allows us to see the power levels of the radiation. He was the 6th child -
Period: to
Marie Curie
From: Poland/France
First discovered and coined the term radioactivity. Also discovered polonium and radium. She learned of radiation by studying the rays coming off of uranium and thorium she discovered the elements when she realized that compounds of uranium and thorium had very high radiation. Made mobile X-Ray Machines for WWII and died due to being exposed to radiation for so long while working. -
Period: to
Robert Millikan
From: Illinois
Found the accurate charge of electrons by using an oil drop experiment. He was awarded the Nobel Prize in Physics. -
Period: to
Ernest Rutherford
From: New Zeland
Discovered the proton and found they were located in the nucleus. Used a gold foil experiment to find this. Rutherfordium is named after him and he went to the University of Cambridge. -
Period: to
Albert Einstein
From: Germany
Discovered the photoelectric effect (causes electricity to be able to flow through light easier than air). He found this by running light over electric arcs. He renounced his German citizenship when he was 16, and his father was an engineer. -
Period: to
Niels Bohr
From: Denmark
Developed a design of the atom with the electrons in fixed patterns around the nucleus. He combined the Quantum theory with Rutherford's knowledge of the structure of atoms. He was a philosopher and a supporter of scientific research. -
Period: to
Erwin Schrödinger
From: Austria
Made a wave formula for electrons in more complex atoms. Used the finding of the Bohr hydrogen atom and the knowledge that electrons are not fixed and can be measured in waves to make his formula. Created the famous Schrödinger's cat paradox. -
Period: to
James Chadwick
From: UK
Discovered the neutron when alpha rays were directed to beryllium there was a very strong amount of radiation. He said it was the neutron particle causing the reaction. He was knighted for his wartime contribution. -
Period: to
Louis De Broglie
From: France
He said particles could also be measured in waves; he sent electrons into crystals then into thin layers of metal. He was of noble heritage. -
Period: to
Werner Heisenberg
From: Germany
Developed the "Uncertainty Relation" which allows for precise measurement of the velocities and movement of particles. This was done using quantum mechanics and matrices. He also worked a lot in plasma physics.