important science dates

  • 440

    greek philospher thought.....

    around 440 bce greek philosopher named democritus thought that you would eventually end up with a particle that could not be cut
  • Apr 22, 600

    600 bc thales of miletus finds something out

    In about 600 B.C. Thales of Miletus discovered that a piece of amber, after rubbing it with fur, attracts bits of hair and feathers and other light objects.
  • elements combining =

    In the late 1700s scientists had learned that elements combine in certain proportions based on mass to form a compound
  • john dalton published his theory

    in 1803 john dalton a british chemist and schoolteacher published his atomic theory.
  • scientists decided that daltons theory explained alought

    toward the end of the 1800s scientists agreed that daltons theory explained much of what they saw.
  • dalton makes a atom model

    In 1897, the English physicist J.J. Thomson discovered the electron and proposed a model for the structure of the atom.
  • J.J found a problem with daltons theory

    In 1897 j.j thomson a british scientist showed that there was a mistake in daltons theory
  • vibrating atoms

    In 1900 Max Planck, a professor of theoretical physics in Berlin showed that when you vibrate atoms strong enough, such as when you heat an object until it glows, you can measure the energy only in discrete units
  • making a new atom model

    1911 rutherford revised the atomic theory he made a new model of the atom
  • neils bohr discovers something with atoms

    1913 niels bohr a danish scientist who worked with rutherford studied the way the atoms react to light which lead him to propose that electrons move around the nucleus in certain path
  • bohrs atom model has troubles to

    By the 1920s, further experiments showed that Bohr's model of the atom had some troubles. Bohr's atom seemed too simple to describe the heavier elements.
  • getting smarter with atoms

    In 1924 a Frenchman named Louis de Broglie thought about particles of matter. He thought that if light can exist as both particles and waves, why couldn't atom particles also behave like waves?