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340
Aristotle's Discovery
He believed in the four elements and also concluded from his theories that all things composed of one of the four, or a combination of the elements. -
460
Democritus
He held the belief that everything has a composition of atoms, which are physically indivisible, and are constantly in motion. He also theorized that the combination of atoms as they moved resulted in changes in matter. -
Oct 12, 1492
Columbus' Voyage
On this day, Columbus reaches the new world. -
Lavoisier
Antoine Lavoisier introduced balance in chemistry and in 1774, began researching the burning process. From his findings he proposed the Combustion Theory. Along with that, Lavoisier proposed the law of Conservation of Mass, which is the theory that mass is neither created nor destroyed in chemical reactions. -
Revolutionary War
The fight of Americans for independence from Britain. -
Berzelius
Berzelius developed a rational system of atomic symbols. He believed it would be easier to use the Latin word for each element, rather than complicated symbols with little relations to the elements. Thus, Berzelius concluded that the element’s symbols would be the first two letters of the Latin name. -
Dalton
John Dalton proposed the Law of Multiple Proportions which was directly followed by the the introduction of the Atomic Theory. This came with a proposal of symbols used to represent the atoms of elements. Dalton also developed the atomic weight scale. -
Avogadro
Amedeo Avogadro proposed a hypothesis that says that gases that have the same temperature, volume, and pressure will contain the same number of molecules. Which is now known as the Avogadro hypothesis. -
The Civil War
The war fought to determine the survival of the Union -
Curie, M.
Marie Curie researched the way that compounds radiate. With much devotion to her studies, she discovered Radium and Polonium. She was often times exposed to high levels of radiation, testing with elements such Uranium and Thorium. Sadly, she passed away from said exposure because at the time, it was not a known danger to us as it is now. -
J.J Thomson
J.J Thomson identified a negatively charged electron was a part of all matter. Thomson introduced the “plum pudding” model of the atom, where the volume of the atom is mainly positive and the small electrons are dispersed through the positive portion to maintain a steady neutral charge. -
Planck
He explained the colors for hot glowing matter by proposing the theory that energy is radiated in specific amounts, rather than in an unbroken wave. Einstein later used his findings to name what we now know as protons. -
Millikan
Robert Millikan discovered the unit of charge of the electron. Using his “oil drop” experiment is how he came to find this. The experiment was conducted by having the atomizer of a bottle spread a liquid into a container withholding the sample. Using gravity as a factor, the droplets that fell to the bottom were those that could not attract any electrons. His discovery was that the charge unit of an electron is e=1.60x10^-9 coulombs. -
Rutherford
Using alpha rays, Rutherford attempted to look on the inside of an atom. In this, he discovered that the positively charged units had zero components, and he believed that the electrons traveled in a pattern similar to that of the orbiting planets in the solar system. He also proposed the idea of there being a proton. -
Bohr
Bohr discovered a problem with Rutherford’s model of the atom, his discrepancy lied within the location of the electrons. His findings concluded that the electrons, instead of going into the nucleus like the protons and neutrons, they are supposed to be traveling around the nucleus. He also discovered that the reason atoms radiate energy is because the electrons are frequently transitioning from high to low energy, which causes an absorption of energy. -
Sinking of the Titanic
The largest ship afloat, sunk four days in to the voyage to New York city -
Moseley
Using x-rays, he studied the structure of the atom. And Moseley is also the major contributor in the right of why we order the elements by atomic number. -
World War I
A global war that was centered in Europe -
Schrodinger
He came up with the wave model of the atom, and compared to the strings of a violin. Before this discovery was made, no one at this point could describe the appearance of an atom, since nothing in our natural world looks anything like it. -
Hesienberg
He proposed the Heisenberg Uncertainty Principle. Which was shown by measuring the certainty of the position of particles. From that principle it is also known that the electrons do not travel in neat orbits. Overall, Heisenberg’s contribution to the atomic theory was the study of the behavior of electrons. -
Chadwick
He discovered the neutron of the atom. His research uncovered the fact that neutrons have a slightly higher amount of mass than the proton. And with that information of the protons and neutrons, Chadwick gave the combination of the two the name “nucleon”. -
World War II
Fought between the Allies and the Axis, the most widespread war in history. Marked by its mass deaths, including the Holocaust. -
Father's Birth
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Mother's Birth
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My Birth
