-
460 BCE
Birth of Democritus
He was born Abdera, Greece. -
400 BCE
Fun Facts
He was known as "The Laughing Philosopher," because he was cheerful at work. -
400 BCE
Contribution to the Atom
Democritus adopted the atomic theory. He thought that matter was made of hard, small, and indivisible particles, called atoms. He also believed all atoms were typically identical, however also thought that a substance's properties were derived from an atom's characteristics. However, his idea was not widely believed. -
370 BCE
Death of Democritus
-
Birth of Antoine Lavoisier
Paris, France. -
Fun Facts
Lavoisier named the elements carbon, hydrogen, and oxygen. -
Contribution to the Atom
Lavoisier discovered the Law of Conservation of Matter, which states that atoms can't be created or destroyed by a chemical reaction. -
Birth of John Dalton
Eaglesfield, Cumbria, United Kingdom -
Death of Antoine Lavoisier
Paris, France -
Fun Fact
John Dalton was colorblind -
Contribution to the Atom
Dalton's atomic theory stated that all matter is made of tiny indivisible particles called atoms. He also said the atoms of one element are the same, but are different from other element's atoms. Dalton created the Law of Multiple Proportions too, which states that all chemical reactions involve the reorganizing of atoms in simpler whole number ratios. -
Death of John Dalton
Manchester, United Kingdom -
J.J. Thomson
Cheetham Hill, Manchester, United Kingdom -
Contribution to the Atom
Thomson discovered the electron by observing cathode rays. -
Birth of Max Planck
Kiel, Duchy of Holstein -
Fun Fact
Planck had a Ph.D. in Physics at the young age of 21 -
Contribution to the Atom
Planck theorized that energy did not go in a steady continuum, but that it was instead administered in quanta (Discrete packets). -
Birth of Marie Curie
Warsaw, Kingdom of Poland, then part of the Russian Empire. -
Fun Fact
Curie was the first woman to win a Nobel Prize. -
Contribution to the Atom
Marie Curie determined that the capacity to radiate was not dependent on the arrangement of atoms in a molecule, and that it must be connected to the interior of the atom. -
Birth of Robert Millikan
Morrison, Illinois, U.S. -
Fun Fact
Millikan was honored with the Nobel Prize for Physics. -
Contribution to the Atom
Millikan was able calculate the value of the negative charge of an electron by organizing an experiment. -
Birth of Ernest Rutherford
Brightwater, New Zealand -
Fun Fact
Rutherford attended Cambridge University in England. -
Contribution to the Atom
Rutherford created an atomic model that presented a small positively charged nucleus that contained positively charged protons and most of the atom's mass, and a large volume around the nucleus where electrons move. He stated that the number of protons was also identical to the number of electrons. Rutherford also later suggested the existence of a neutral particle being in the nucleus in order to make up for the mass deficiency in the atoms he studied. -
Birth of Albert Einstein
Ulm, Kingdom of Wurttemberg, German Empire -
Contribution to the Atom
Einstein's most famous contribution was the Theory of Relativity because it put down the foundation for the release of atomic energy. He was also able to analyze Brownian motion and give good verification that atoms and molecules did indeed exist. -
Fun Fact
Einstein rewrote the law of gravitaion -
Birth of Niels Bohr
Copenhagen, Denmark -
Fun Fact
Bohr founded the Institute of Theoretical Physics at the University of Copenhagen, which was later renamed the Niels Bohr Institute. -
Contribution to the Atom
Bohr presented a "planetary" model for the hydrogen atom that demonstrated that electrons move around the nucleus with a constant energy in fixed orbits. It also showed that even though electrons only can exist in discrete energy levels, that excited electrons can move to a higher orbit by absorbing energy, or fall back to their original orbit by releasing energy as radiation. -
Birth of Erwin Schrodinger
Vienna, Austria -
Fun Fact
Schrodinger grew up bilingual because his grandmother was British. -
Contribution to the Atom
Schrodinger was able to describe the likelihood of being able to find an electron in a specific position by using mathematical equations. -
Birth of James Chadwick
Bollington, United Kingdom -
Birth of Louis De Broglie
Dieppe, France -
Fun Fact
De Broglie's first degree was in history but he earned subsequent degrees in mathematics and physics. -
Contribution to the Atom
De Broglie helped create the Wave Mechanics Theory. This theory stated that electrons are able to act as both particles and waves. It also showed that when electrons in the orbit around the nucleus produce waves, they set up a wave of a specific energy, frequency, and wavelength. -
Birth of Werner Heisenberg
Wurzburg, Germany -
Contribution to the Atom
Heisenberg was responsible for the creation of quantum mechanics, which led to the finding of allotropic forms of hydrogen. He is also famous for creating the Heisenberg Uncertainty Principle, which stated that it is not possible to accurately find the position and momentum of an electron simultaneously. -
Fun Fact
Thomson became the Master of Trinity College in 1918 and held the position until his death. -
Contribution to the Atom
Chadwick discovered that the nucleus of an atom contains electrically neutral particles with a mass similar to the mass of a proton, called neutrons. -
Death of Marie Curie
Passy, Haute-Savoie, France -
Fun Fact
Chadwick was awarded the 1935 Nobel Prize in Physics. -
Death of Ernest Rutherford
Cambridge, United Kingdom -
Death of J.J. Thomson
Cambridge, United Kingdom -
Death of Max Planck
Gottingen, Lower Saxony, Germany -
Fun Fact
Heisenberg lectured at Cambridge -
Death of Robert Millikan
San Marino, California, U.S. -
Death of Albert Einstein
Princeton, New Jersey, U.S. -
Death of Erwin Schrodinger
Vienna, Austria -
Death of Niels Bohr
Copenhagen, Denmark -
Death of James Chadwick
Cambridge, United Kingdom -
Death of Werner Heisenberg
Munich, Germany -
Death of Louis De Broglie
Louveciennes, France
