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440 BCE
Disagreement
Aristotle disagreed and stated that matter was made of four elements water, wind, earth, fire. and others agreed. -
440
What is stuff made of?
Democritus proposed everything in the world is made up of tiny particles. With empty space around it, also speculated that there are different shapes and sizes of atoms. -
Atoms remembered
John Dalton showed that common substances always broke down into the same elements in the same proportions. John Dalton stated that common substances always broke down to the same atoms in the same proportions. John Dalton stated the atoms could neither be created or destroyed. -
Atom discovery
J.J. Thompson discovered the electron and found atoms were spheres packed with positive charged atoms filled with negatively charged electrons. -
Father Of The Nuclear Age
Ernest Rutherford shot positively charged alpha particles at a sheet of gold foil and found out that most can go through but some bounce back. So, some particles bounce back from a dense positively charged nucleus. -
Another Discovery
Neils Bohr discovered that electrons orbit the nucleus at fixed energies and distances, but experiments have shown that the electrons move in waves around the nucleus. -
Solar system model
Galileo c. Ptolemy b. Copernicus created the solar system model -
Erwin Schrodinger
In 1926 Erwin Schrodinger expained the movement of electrons in an atom. He concluded that it was a wave of motion. He called this idea Wave Mechanics. His discovery was the first to explain the movement of electrons with visuals, and the second to explain the idea. -
Position and Speed
Werner Heisenberg discovered it is impossible to determine the exact position and speed of electrons as they move around an atom.
