-
200
Democritus- 440 BC
He discovered the atom.He therozied that eventually you would end up with a material that can not be cut. -
200
Aristotle- BC
Aristotle disagreed with Democritus, he belived that you could always cut the material. He was so convinicing that many people belived him for years. -
Dalton
Dalton published the atomic theory in 1803. He stated that all substances are made up of atoms, atoms can not be destroyed, created or divided,all atoms are the same, atoms of different substances are different, atoms will join with each other to create other substances. -
Thomson
Thomson discovered that there are small particles inside the atom. Atoms can be divided. He discovered negativley charged particles inside the atom. They are now called electrons. -
Rutherford 1909
Rutherford shone a positively charged beam through a gold tin sheet. He could see the particles. Rutherford discovered that they are not blobs like Thomson theorized, but small hard and can deflect the beam. -
Rutherford 1911
Rutherford had another scientific breakthrough. He made a new model of the atom. He proposed that in the center of the atom there is a dense positivley charged ball. The nucleus. Positivley chargesd particles would be repelled away from the nucleus. He theorrized that the nucles is 100,000 times smaller than the atom itself. -
Bohr
Bohr studied the way that atoms react to light. His results led him to believe that electrons move around the nucleus in certain patterns or energy levels. -
Schrodinger and Heisenburg
Schrodinger and Heisenburg discovered that Bohr was wrong. That electrons do not move in certain patters. The path can not be predicted.
