Lelani T 1

Democritus

400 BCE

Name: Democritus Major findings: that all material bodies are made up of indivisibly small “atoms.”

Plato

347 BCE

Name: Aristocles, Major findings: he had developed an insightful analogy between harmony in the state and harmony in the individual.

Aristotle

322 BCE

Name: Aristotle Major findings: he invented the scientific method of analysis.

The Alchemists

1771

Name: Daniel Alan Maman Major findings: to pursue your dreams by following what your heart desires.

Lavoisier

1783

Name: Lavoisier Major findings: he reacted oxygen with inflammable air, obtaining "water in a very pure state."

John Dalton

1803

Name: John Dalton Major Findings: he discovered oxygen combined with either one or two volumes of nitric oxide in closed vessels over water.

Newton's Law of Octaves

Feb 7, 1863

Name: Newlands law of octaves. Major finding: the law of octave states that every eighth element has similar properties when the elements are arranged in the increasing order of their atomic masses.

Mendeleev's Pd. Table

Feb 17, 1869

Name: Mendeleev;s Pd Table Major findings: he had discovered that, when all the known chemical elements were arranged in order of increasing atomic weight, the resulting table displayed a recurring pattern, or periodicity, of properties within groups of elements.

Discovery of Radioactivity

Mar 1, 1896

Name: Henri Becquerel Major findings: the studies of radioactivity have been studied for years and discovered the elements polonium and radium after chemically extracting uranium from the ore.

Discovery of the electrons

1897

Name: Thomson Joseph John Thomson Major findings: J. J. Thomson won a Nobel Prize in 1906 for discovering the elementary particle electron. Also Interestingly, his son G. P. Thomson had won the Nobel Prize in 1937 for proving the wavelike properties of electron.

Plum Pudding Model

1904

Name: Thomson's “Plum Pudding” Model. Major findings: experiments with cathode ray tubes had showed that all atoms contain tiny negatively charged subatomic particles or electrons.

Photoelectric Effect

1905

Name: Photoelectric Effect Major findings: photoelectric effect, phenomenon in which electrically charged particles are released from or within a material when it absorbs electromagnetic radiation.

Planck's Quantum Theory of Light

1905

Name: A photon. Major findings that the energy of light is proportional to frequency.

Rutherford's Gold Foil Experiment

1908

Name: The Geiger–Marsden experiments Major findings: A piece of gold foil had been hit with alpha particles, which had a positive charge. And most alpha particles went right through. it had also showed that the gold atoms were mostly empty space.

Discovery of the protons

1909

Name: Ernest Rutherford Major findings: Emest Rutherford research resulted in a reaction which led to the very first splitting of atom.

Charge of the Electron

1909

Name: Change of electron Major Findings: discovered the electron by experimenting with a Crookes, or cathode ray, tube.

Mosley's Atomic Numbers

1913

Name: Mosley's Atomic Numbers Major findings: In 1914 Moseley had published a paper in which he concluded that the atomic number is the number of positive charges in the atomic nucleus.

Robert Millikan

1913

Name: Robert Andrews Millikan Major findings: Roberts earliest major success was the accurate determination of the charge carried by an electron.

Bohr's Planetary Model

Mar 6, 1913

Name: Rutherford–Bohr model Major findings: The Bohr Model is a planetary model in which the negatively charged electrons orbit a small, positively charged nucleus similar to the planets orbiting the sun (except that the orbits are not planar).

Schrodinger Equation

1926

Name: Schrödinger wave equation, Major findings: that a wave equation that accurately calculated the energy levels of electrons in atoms.

Heisenberg Uncertainty Principle

1927

Name: Heisenberg uncertainty principle or indeterminacy principle Major findings: we can't know both the position and speed of a particle such as a photon or electron with perfect accuracy.

Discovery of the Neutron

1932

Name: James Chadwick Major finding: He had been awarded the Nobel Prize in Physics in the year 1935 for this discovery.