-
450
Democritus(430 B.C.)
Democritus believed that everything in the world consists of an infinite number of atoms. They are invisible particles of matter that are ungenerated and indestructible. He also believed that atoms are connected by hooks and barbs. Democritus believed that the atom looked like similar to a marble, completely solid. Democritus's method was watching decay and mixing of elements laid out by the Eleatics. -
450
Aristotle( 343 B.C.)
Aristotle believed that all materials on Earth were not made of atoms, but of earth, fire, water, and air. He believed all substances were made of small amounts of these four elements of matter. Through observation is how he made his discoveries and theories. He dissected plants and animals to learn how they functioned. -
John Dalton
Dalton believed that matter consists of indivisible atoms that arrange in different combinations to create compounds. He believed that the atom looked liked tiny balls arranged differently. Dalton made his discoveries by studying meteorology and becoming interested in gases and their components. -
J. J. Thompson
Thompson discovered that electricity passing through a gas causes the gas to give off particles that were too small to be atoms. They gave off an electric charge, so he called them electrons. He believed that the electrons were sprinkled around the atom like raisins in a loaf of raisin bread. Thompson made his discoveries by passing electricity through a gas. -
Ernest Rutherford
Rutherford discovered that atoms has a necleus and more importantly found out that instead of the electrons being randomly spread out through this positively charged "pudding", that positive energy came from a single concentrated place. Besides discovering the necleus, he also discovered protons. He was able to figure this all out through his gold foil experiment where he shot particles at the foil, and when it curved it showed him that there something with a large + energy -
Niels Bohr
Bohr discovered the shells around the nucleus of an atom. He believed that electrons travel around the nucleus in a stationary orbit. He also thought that if an electron dropped from a higher level to a lower level, that it has to release energy. Neils Bohr's method was applying the quantum theory to Rutherford's experiments. He made planetary models of the atom to show the atomic spectrum. -
Werner Karl Heisenurg
He believed in the uncertainty principle. In order to view an electron's orbit, one must shine a wave of light energy smaller than the electron. The electron will absorb the energy and the absorbed energy will cause the electron to move positions. Heisenburg made this discovery by shining light energy into electrons and performing experiments. -
Erwin Shrodinger
Schrodinger thought that electrons were arranged in orbitals that were distributed within electron clouds. He stated that an orbital is the space that surrounds a nucleus where the electrons move. The first shell containes two electrons and the second had eight. He obtained this information by -
