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400 BCE
Democritus
In 442 BC, a theory was created. This theory was called the atomic theory. It's belief. is that the universe is composed of two elements, the atoms and the void. In 465 BC, Democritus hypothesized that atoms can't be destroyed, differ in size,shape, temperature, always moving, and invisible. He created the first atomic model. -
John Dalton
In 1803, John Dalton created the atomic theory of matter. The theory states that all elements are made out of atoms and is impossible to divide or destroy an atom. Dalton
published Meteorological Observations in 1787. He discovered color blindness. He experimented with gases which led to his theory in 1803. -
J J Thompson
In 1897, Thompson accidentally discovered the electron while doing an experiment with gas discharge tubes. In 1883, he became a lecturer until in 1918, he became a master. He realized that an atom can be divided. He made the Plum Pudding model. This model was developed before the atomic nucleus was discovered. -
Rutherford
In 1908, Rutherford conducted the gold foil experiment. The outcome of this experiment was that atoms are made of a small positive nucleus. Atoms are mostly empty space. In 1894, he was awarded the 1851 Exibition Science Scholarship. One of his first researches was magnetic properties of iron exposed to high-frequency oscillations. In 1896, he published the Transactions of the New Zealand. -
Bohr
In 1913, Bohr created a theory for the hydrogen atom. This theory is base on the quantum theory that energy is transferred in certain quantities. His theory is that electrons need to move around the nucleus but in orbits. When the orbit jumps into another orbit with low energy, a light quantum is emitted. (https://www.nobelprize.org/nobel_prizes/physics/laureates/1922/bohr-facts.html) Bohr received the Nobel Prize in Physics in 1922, for understanding in the atomic structure and quantum theory.
