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460 BCE
Democritus's Birth
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432 BCE
The Construction of the Parthenon
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400 BCE
Democritus' discovery
Proposed the idea of atomos (indivisible particles). Suggested that all matter is composed of small, indestructible units called atoms. This concept laid the groundwork for the atomic theory but lacked experimental evidence. -
370 BCE
Democritus's Death
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John Dalton's Birth
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Michael Faraday DOB
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John Daltons Discovery
Developed the Atomic Theory, stating that elements are made of atoms, each aspect has identical atoms, and atoms combine in fixed ratios to form compounds. This helped explain chemical reactions and conservation of mass. -
THe Louisiana Purchase
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Michael Faraday Date of Discovery
Discovered the principles of electromagnetic induction and electrolysis.
Showed that atoms are associated with electrical charges, paving the way for the idea that atoms could have internal structures like electrons. -
John Daltons Death
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Eugen Goldstein DOB
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JJ Thomson DOB
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Michael Faraday DOD
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Robert Millikan DOB
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Ernest Rutherford DOB
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Neils Bohr DOB
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Eugen Goldstein Date of Discovery
Discovered canal rays (positive rays), leading to the discovery of protons. -
Edwin Schrödinger DOB
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James Chadwick DOB
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“nuclear” model
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JJ Thomson's Discovery
Discovered canal rays (positive rays), leading to the discovery of protons.
His work suggested that atoms contain positively charged particles, challenging the idea that atoms were indivisible.
Also discovered Electrons -
The Spanish American War
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Werner Heisenberg DOB
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“plum pudding” model
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Robert Millikan Discovery
Conducted the Oil Drop Experiment, measuring the charge of the electron and confirming the quantization of electric charge. -
Ernest Rutherford Discovery
Proposed the nuclear model, showing that atoms have a small, dense, positively charged nucleus surrounded by electrons. -
Neils Bohr Discovery
Developed the Bohr Model, where electrons orbit the nucleus in fixed energy levels, explaining hydrogen line spectra and introducing quantized electron energy levels. -
Period: to
World War I
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Edwin Schrödinger's Dicovery
Developed the Quantum Mechanical Model, introducing the Schrödinger equation that describes electrons as wavefunctions, giving a more accurate depiction of electron distribution. -
Werner Heisenbergs DIscovery
Formulated the Heisenberg Uncertainty Principle, which states that the position and momentum of an electron cannot be precisely determined simultaneously, introducing the concept of probability clouds for electron positions. -
The Great Depression
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Eugen Goldstein DOD
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JJ Thomson DOD
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James Chadwick's DIscovery
Discovered the neutron, a neutral particle in the nucleus, completing the basic understanding of atomic structure and advancing nuclear physics. -
James Chadwick's DIscovery
Discovered the neutron, a neutral particle in the nucleus, completing the basic understanding of atomic structure and advancing nuclear physics. -
Adolf Hitler becoming Chancellor of Germany
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Ernest Rutherford DOD
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Ernest Rutherford DOD
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Period: to
World War II
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Robert Millikan DOD
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Edwin Schrödinger DOD
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Neils Bohr DOD
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James Chadwicks's DOD
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Wener Heisenburg DOD