-
around 440 bce greek philosopher named democritus thought that you would eventually end up with a particle that could not be cut
-
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.
-
In the late 1700s scientists had learned that elements combine in certain proportions based on mass to form a compound
-
in 1803 john dalton a british chemist and schoolteacher published his atomic theory.
-
toward the end of the 1800s scientists agreed that daltons theory explained much of what they saw.
-
In 1897, the English physicist J.J. Thomson discovered the electron and proposed a model for the structure of the atom.
-
In 1897 j.j thomson a british scientist showed that there was a mistake in daltons theory
-
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
-
1911 rutherford revised the atomic theory he made a new model of the atom
-
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
-
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.
-
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?