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Antonie Lavosier
He proposed the Combustion Theory which was based on sound mass measurements. He named oxygen. He also proposed the Law of Conversation of Mass which represents the beginning of modern chemistry. -
Joseph Proust
Proposed the the Law of Constant Composition -
John Dalton
Dalton's theory was based on the premise that the atoms of different elements could be distinguished by differences in their weights. -
Amadeo Avagadro
His hypothesis says that at the same temperature and pressure, equal volumes of gases contain the same number of molecules or atoms. -
Henri Becquerel
While studying the effect of x-rays on photographic film, he discovered some chemicals spontaneously decompose and give off very penetrating rays. -
William Crookes
Studied the effects of sending an electric current through a gas in a sealed tube. The tube had electrodes at either end and a flow of electrically charged particles moved from one of electrodes. This electrode was called the cathode, and the particles were known as cathode rays. -
J.J. Thomson
Discovered the electron in a series of experiments designed to study the nature of electric discharge in a high-vacuum cathode-ray tube, he estimated the value of the charge itself. -
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. http://youtu.be/ZEV4KJBJvEg -
Max Planck
used the idea of quanta (discrete units of energy) to explain hot glowing matter. -
Robert Millikan
Determined the unit charge of the electron with his oil drop experiment at the University of Chicago. Thus allowing for the calculation of the mass of the electron and the positively charged atoms. -
Crayon
Edward Binney and Harold Smith co-invent crayons. -
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Ernest Rutherford
Established that the nucleus was very dense, very small and positively charged. He also assumed that electrons were located outside outside the nucleus, -
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. -
WWI
WWI started when the Archduke and heir to the Austria Hungary throne, Franz Ferdinand and his wife Sofia, were assassinated. -
WWI Ends
WWI ends with the treaty of Versailles. -
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 successive orbital shells of electrons. http://youtu.be/wCCz20JOXXk -
Louis deBroglie
His theory of particle-wave duality that particles can behave like waves, and waves (radiation) can behave like particles. -
Chiang Kai-shek
Chinese leader Chiang Kai-shek come into power. -
Louis deBroglie
Described atoms by means of formula connected to the frequencies of spectral lines. Proposed Principle of Indeterminacy - you can not know both the position and velocity of a particle. -
Violence in Jerusalem
Jewish-Arab large scale violence in Jerusalem -
Erwin Schrodinger
Viewed electrons as continuous clouds and introduced "wave mechanics" as a mathematical model of the atom http://youtu.be/tj9Pt8WgQM8. -
Pluto
Astronomers discover Pluto, the ninth planet. -
Nobel Prize
Chemistry: Hans Fischer (Germany), for work on coloring matter of blood and leaves and for his synthesis of hemin -
James Chadwick
Using alpha particles discovered a neutral atomic particle with a mass close to a proton. Thus was discovered the neutron. -
Pearl Harbor
The attack on Pearl Harbor was a surprise military strike conducted by the Imperial Japanese Navy against the United States naval base at Pearl Harbor, Hawaii. -
Hiroshima, Japan
This atomic bomb, the equivalent of 20,000 tons of TNT, flattened the city, killing tens of thousands of civilians. While Japan was still trying to comprehend this devastation three days later, the United States struck again, this time, on Nagasaki. -
WWII
WWII The Second World War began in September 1st 1939 with Hitler's attack on Poland, Europe. -
WWII Ends
WWII came to an end on May 1945 with the surrender of Germany in Europe and North Africa. -
Aristotle
He believed in the four elements of air, earth, water and fire. Aristotle felt that regardless of the number of times you cut a form of matter in half, you would always have a smaller piece of that matter. This view held sway for 2000 years primarily because Aristotle was the tutor of Alexander the Great. http://youtu.be/BeJJpbDrVRM
