Atom with electrons

The Atom by Emily Snider

  • Jan 1, 1000


    415 B.C. The first person to come up with theory that different kinds of atoms have different shapes. Also realized that matter was made up of small individual atomos.
  • Jan 1, 1000


    353 B.C. Disagreed with Democritus' theory. Aristotle's theory said that matter could be divided an infinite number of times.
  • Antoine Lavosier

    Antoine Lavosier
    First person to make good use of a balance. He also proposed the Combustion Theory and named oxygen and came up with the Law of Conservation of Mass.
  • Joseph Proust

    Joseph Proust
    Joseph proposed the Law of Constant Composition.
  • John Dalton

    John Dalton
    Did many experiments with different chemicals. With these experiments he came up with the atomic theory.
  • Amadeo Avagadro

    Amadeo Avagadro
    Proposed the Avagadro's Hypothesis that stated that at the same temperature and pressure, equal volumes of gases contain the same number of molecules or atoms.
  • First Vulcanized Rubber Soccer Ball

    First Vulcanized Rubber Soccer Ball
    Charles Goodyear patented the first vulcanized rubber soccer ball in this year.
  • First Rules of Soccer

    First Rules of Soccer
    The modern version of the game was standardized by the English on this date.
  • First Soccer Organization

    First Soccer Organization
    On this date many soccer clubs got together and formed the first major soccer club.
  • Iowa State's First Class of Graduates

    Iowa State's First Class of Graduates
    The first class of students from Iowa State University graduated this on year.
  • William Crookes

    William Crookes
    Studied cathode ray tubes which are negatively charged. By studying these he learned about deflection of cathode rays by magnetic fields.
  • Henri Becquerel

    Henri Becquerel
    He discovered that uranium containing minerals produced x-ray radiation.
  • Utah's Admittance

    Utah's Admittance
    On this date Utah was admitted as the 45th U.S. State.
  • J.J. Thompson

    J.J. Thompson
    Discovered the electron and made a structure for them. He knew that electrons had a negative charge so he came to the conclusion that matter had a positive charge.
  • Madame (Marie) Curie

    Madame (Marie) Curie
    She studied uranium and thorium and called the spontaneous decay process "radioactivity". She and her husband discovered the radioactive elements polonium and radium.
  • Max Planck

    Max Planck
    Discovered the quanta. He noticed that when atoms vibrate long enough you can measure their energy only in discrete units called quantas.
  • Albert Einstein

    Albert Einstein
    He published the famous equation E=mc2 and the Theory of General Relativity.
  • Robert Millikan

    Robert Millikan
    Robert determined the charge of an electron using his oil drop apparatus.
  • Ernest Rutherford

    Ernest Rutherford
    He realized that atoms must get scattered by small pieces of positively charged matter. So he concluded that electrons must exist somewhere. Then in 1920 he discovered the name proton.
  • Henry Moseley

    Henry Moseley
    He concluded that the atomic number was equal to the positive charge of an atom.
  • Niels Bohr

    Niels Bohr
    He made a more accurate model of the atom.
  • Louis de Brogile

    Louis de Brogile
    He introduced that wave/particle durality of matter.
  • Werner Heisenberg

    Werner Heisenberg
    He came up with the Heisenberg Uncertainty Principle which takes away the idea of electrons traveling around in neat orbits. Any electron that is subjected to photons will have its momentum and position affected.
  • Erwin Schrodinger

    Erwin Schrodinger
    Used Brogile and other's ideas and made an equation. Solving the equation can predict the properties and reactivities of all atoms and molecules.
  • James Chadwick

    James Chadwick
    James discovered the neutron. He also proved that neutrons, neutral particles in the nucleus made up approximately half the mass of an atom, actually did exist.
  • Pearl Harbor

    Pearl Harbor
    The attack on pearl harbor by Japanese Imperial General Headquarters.
  • First Computer

    First Computer
    The first computer was made at Iowa State University.
  • Radium E.

    Radium E.
    Radium E. becomes the radiactive element to be made synthetically.
  • 5th Winter Olympics

    5th Winter Olympics
    The 5th Winter Olympic began in St. Moritz, Switzerland.
  • Start of the Korean War

    Start of the Korean War
    The Korean war started on this date and ended on July 27, 1953.