Scientists

By cnieto6220
  • 400 BCE

    Democritus

    Democritus believed that matter was made up of extremely small particles. They called these particles atoms which comes from an ancient Greek word meaning 'indivisible'.
  • 336 BCE

    Aristotle

    Aristotle did not believe in the atomic theory. He believed that all materials were made of four elements earth, fire, water, and air.

  • Antonio Lavoiser

    Antonio Lavoiser his results led to one of the fundamentals laws of chemical behavior the law of conservation of matter

  • Joseph Louis Proust

    Joseph Louis Proust published his Law of Definite Proportions in 1794. This law states that a compound is composed of exact proportions of elements by mass regardless of how the compound was created.

  • John Dalton

    John Dalton says all matter was composed of atoms, indivisible and indestructible building blocks. While all atoms of an element were identical different elements had atoms of different size and mass.

  • Michael Faraday

    Michael Faraday In the 1830's, Michael Faraday, a British physicist, made one of the most significant discoveries that led to the idea that atoms had an electrical component.

  • Henri Becquerel

    Henri Becquerel French physicist who discovered radioactivity through his investigations of uranium and other things. In 1903 he shared the Nobel Prize for Physics with Pierre and Marie Curie.

  • J.J Thompson

    In 1897 J.J. Thomson discovered electrons and noticed that an atom can be divided. He also said that atoms are made of positive and negative cores.

  • Marie & Pierre Curie

    Marie and Pierre Curie are best known for their work in radioactivity, They are also known for to help with the discovery of radium and polonium.

  • Max Planck

    Max Planck a German Physicist best known for his quantum theory of energy. He is also famous for describing spectral density and electromagnetic density.

  • Albert Einstein

    Albert Einstein treated matter and energy as exchangeable. In 1905 Albert Einstein became famous for the theory of relativity, which laid the basis for the release of atomic energy

  • Ernest Rutherford

    Robert Millikan determined the unit charge of the electron in 1909 with an oil drop experiment an experiment done at the University of Chicago. He made this calculation e = 1.60 x 10-19 coulombs.

  • Niels Bohr

    In 1913, Niels Bohr proposed a theory for the hydrogen atom based on quantum theory that energy is transferred only in certain well defined quantities. Electrons should move around the nucleus but only in certain orbits. When jumping from one orbit to another with lower energy, a light quantum is showed

  • James Chadwick

    In 1932, James Chadwick bombarded beryllium atoms with alpha particles. A radiation was produced.Chadwick interpreted this radiation as being composed of particles with a neutral electrical charge and the approximate mass of a proton.