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Period: 300 to
Chemistry Timeline
-20 Scientists
-10 Inventions -
460
Democritus
The real date of the even is 460 B.C.
His ideas was that matter is composed of empty space through which atoms move. -
Antonie Lavosier
He used this experiment to help himself come up with the Law of Conservation. The law states that matter cannot be made or destroyed. He also hints at the rearrangement of matter in reactions. Matter rearranged, but never disappeared. -
Joseph Proust
Came up with the Law of Definite Proportions which states that a compound is composed of exact proportions of elements by mass regardless of how the compound was created. -
John Dalton
Proposed an "atomic theory" with spherical solid atoms based upon measurable properties of mass. -
Amadeo Avagadro
Avogadro's molecular theory related gas densities to molecular weights, explained reacting proportions by volume in terms of molecular ratios and compositions, and suggested methods for determining both molecular weights and compositions. -
Thomas Edison-Electrographic Vote Recorder
The device was made with the goal of helping legislators in the US Congress record their votes in a quicker fashion than the voice vote system. -
Thomas Edison--Stencil Pen
Edison invented the ancestor of the tattoo gun -- the pneumatic stencil pen. This electric pen, which Edison patented in 1876, used a rod tipped with a steel needle to perforate paper for printing purposes. -
Thomas Edison-Phonograph
Considered to be the first great Thomas Edison invention, and his life-long favorite, the phonograph would record the spoken voice and play it back. -
Thomas Edison--Carbon Transmitter
In 1877, Edison developed the carbon transmitter, a device that improved the audibility of the telephone by making it possible to transmit voices at higher volume and with more clarity. -
William Crookes
Link Discovered cathode rays had the following properties: travel in straight lines from the cathode; cause glass to fluoresce; impart a negative charge to objects they strike; are deflected by electric fields and magnets to suggest a negative charge; cause pinwheels in their path to spin indicating they have mass. -
Thomas Edison--Magnetic One-Separator
Probably the biggest financial failure of Edison's career was the magnetic ore-separator. The idea, which Edison's laboratory experimented with during the 1880s and 1890s, was to use magnets to separate iron ore from unusable lower-grade ores. -
Thomas Edison--Preserving Fruit
In 1881, Edison filed for a patent for a method to preserve fruits, vegetables or other organic substances in a glass vessel. The vessel was filled with the items to be preserved, and then all the air was sucked from it with an air pump. The vessel tube was sealed with another piece of glass. -
Thomas Edison--Webermeter
Edison solved this problem by patenting the Webermeter in 1881. The Webermeter contained two or four electrolytic cells with zinc at both electrodes and a zinc sulfate solution. The zinc transferred from one electrode to the other at a set rate as electricity was used. The meter reader removed the electrolytic cells at each reading for weighing, replacing them with new ones. -
Henri Becquerel
https://www.youtube.com/watch?v=b03IW4fgl30 While studying the effect of x-rays on photographic film, he discovered some chemicals spontaneously decompose and give off very pentrating rays. -
J.J. Thomson
Used a CRT to experimentally determine the charge to mass ratio (e/m) of an electron =1.759 x 10 8 coulombs/gram. Studied "canal rays" and found they were associated with the proton H + . -
Madame Curie
Studied uranium and thorium and called their spontaneous decay process "radioactivity". She and her husband Pierre also discovered the radioactive elements polonium and radium. -
Thomas Edison--Alkaline Battery
Edison believed cars would be powered by electricity, and in 1899 he began to develop an alkaline storage battery that would power them. -
Max Planck
Postulated a "Saturnian" model of the atom with flat rings of electrons revolving around a positively charged particle. -
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Robert Millikan
Oil drop experiment determined the charge (e=1.602 x 10 -19 coulomb) and the mass (m = 9.11 x 10 -28 gram) of an electron. -
Ernest Rutherford
https://www.youtube.com/watch?v=45TGJRBFLNc Using alpha particles as atomic bullets, probed the atoms in a piece of thin (0.00006 cm) gold foil . He established that the nucleus was: very dense,very small and positively charged. He also assumed that the electrons were located outside the nucleus. -
Thomas Edison--Concrete Furniture
Made with air-impregnated foam to keep the weight at only one-and-a-half times that of wooden furniture, Edison's line of concrete furnishings would be sanded and smoothed into a mirror-like finish or stained to look like wood grain. -
Henry Moseley
Using x-ray tubes, determined the charges on the nuclei of most atoms. He wrote"The atomic number of an element is equal to the number of protons in the nucleus". This work was used to reorganize the periodic table based upon atomic number instead of atomic mass. -
Thomas Edison--Spirit Phone
Taking the idea of the telephone and the telegraph a bit further, Edison announced in October of 1920 that he was working on a machine to open the lines of communication with the spirit world. Even though Edison died before it came out. -
Niels Bohr
Developed an explanation of atomic structure that underlies regularities of the periodic table of elements. His atomic model had atoms built up of sucessive orbital shells of electrons. -
Louis de Broglie
Discovered that electrons had a dual nature-similar to both particles and waves. Particle/wave duality. Supported Einstein. -
Werner Heisenberg
Described atoms by means of formula connected to the frequencies of spectral lines. Proposed Principle of Indeterminancy: you can not know both the position and velocity of a particle. -
Erwin Schrodinger
Viewed electrons as continuous clouds and introduced "wave mechanics" as a mathematical model of the atom. -
James Chadwick
https://www.youtube.com/watch?v=73JJRLd8Yio Using alpha particles discovered a neutral atomic particle with a mass close to a proton. Thus was discovered the neutron. -
Aristotle
Aristotle promoted the idea that the universe was made from Earth, air, fire, and water. He did not believe in the atom theory.
