Images

Timeline of Development of Atom

By Audd
  • 500 BCE

    LEUCIPPUS

    LEUCIPPUS
    Leucippus (500- 401BCE) Leucippus is named by most sources as the originator of the theory that the universe consists of two different elements, which he called 'the full' or 'solid,' and 'the empty' or 'void'.
  • Period: 500 BCE to

    THE DEVELOPMENT OF ATOMIC THEORY (click each one)

    The earliest ideas about the atom started from the early Greek philosophers including Thales of Miletus, Empedocles, Leucippus, Democritus, Lucretius, and Aristotle. The seventeenth century known as the rise of experimental science: Sir Francis Bacon, Robert Boyle, Antoine Laurent Lavoisier, and John Dalton. The period from the nineteenth century up to present is considered the golden years of science: Thomson, Rutherford, Bohr, and Sommerfeld.
  • 460 BCE

    DEMOCRITUS

    DEMOCRITUS
    Democritus (460-370 BCE) Democritus was a central figure in the development of the atomic theory of the universe. He theorized that all material bodies are made up of indivisibly small “atoms.”
  • 384 BCE

    ARISTOTLE

    ARISTOTLE
    Aristotle (384- 322 BCE) Aristotle was one of the greatest philosophers who ever lived and the first genuine scientist in history. He made pioneering contributions to all fields of philosophy and science, he invented the field of formal logic, and he identified the various scientific disciplines and explored their relationships to each other.

  • JOHN DALTON

    JOHN DALTON
    John Dalton (1766-1844) John Dalton is best known for what became known as Dalton’s law, which posits that the total pressure of a gaseous mixture is equal to the sum of the partial pressures of the individual component gases, partial pressure being the pressure that each gas would exert alone within the volume of the mixture at the same temperature.

  • J.J THOMSON

    J.J THOMSON
    J. J. Thomson (1856-1940) In 1897 Thomson discovered the electron and then went on to propose a model for the structure of the atom. His work also led to the invention of the mass spectrograph.

  • ROBERT MILIKAN

    ROBERT MILIKAN
    Robert Millikan (1868-1953) Robert Millikan was a physicist who discovered the elementary charge of an electron using the oil-drop experiment.

  • ARNOLD SOMMERFELD

    ARNOLD SOMMERFELD
    Arnold Sommerfeld (1868-1951) As a professor of theoretical physics at Munich (1906–31), he did his most important work. His investigations of atomic spectra led him to suggest that, in the Bohr model of the atom, the electrons move in elliptical orbits as well as circular ones.

  • ERNEST RUTHERFORD

    ERNEST RUTHERFORD
    Ernest Rutherford (1871-1937) Ernest Rutherford postulated the nuclear structure of the atom, discovered alpha and beta rays, and proposed the laws of radioactive decay. He received the Nobel Prize in Chemistry in 1908.

  • NEIL BOHR

    NEIL BOHR
    Niel Bohr (1885-1962) Niels Bohr proposed a model of the atom in which the electron was able to occupy only certain orbits around the nucleus. This atomic model was the first to use quantum theory, in that the electrons were limited to specific orbits around the nucleus.

  • ERWIN SCHRODINGER

    ERWIN SCHRODINGER
    Erwin Schrödinger (1887-1961) Erwin Schrödinger is best known for the Schrödinger equation, which describes the evolution of the wave function, a quantity that describes the wave properties of a particle.

  • JAMES CHADWICK

    JAMES CHADWICK
    James Chadwick (1891-1974) In 1932, Chadwick made a fundamental discovery in the domain of nuclear science: he proved the existence of neutrons – elementary particles devoid of any electrical charge.