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Democritus
- lived from 460BC - 370BC in Abdera, Greece
- proposed that matter was made up of small, hard, indivisible particles, which he called atoms
- no experiments were conducted
- was a happy-go-lucky person who always saw the amusing side of things; known as the ‘Laughing Professor’
- lived for almost a hundred years
- called the ‘Father of modern Science’
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John Dalton
- lived from 1766 - 1844 in Eaglesfield, England
- discovered chemical reactions consist of rearranging atoms in simple whole number ratios
- collected data of ratio of oxygen masses to state his belief that matter exists as atoms
- both of his parents were Quakers
- awarded the Society’s Royal Medal for his Atomic Theory
- had a series of strokes, eventually died from one
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Albert Einstein
- lived from 1879 - 1955 in Ulm, Germany but moved to Switzerland
- provided powerful confirmation that atoms and molecules actually exist, through his analysis of Brownian motion
- analyzed Brownian motion
- created famous equation E=mc2, stating energy and matter can be converted into one another
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Niels Bohr
- lived from 1885 - 1962 in Denmark’s capital city, Copenhagen
- revealed atoms were made up of a tiny dense positively charged nucleus
- wavelength and frequency of the different colors of light can be fitted to a formula – the Balmer Formula
- experimented with hydrogen at high temperatures
- corrected mistakes in his school's’ textbooks as a teen
- ‘corrected’ other students, getting into fights at school, which he usually won
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James Chadwick
- lived from 1891 - 1974 in Bollington, England
- discovered the neutron
- using polonium as a source of (what he believed were) neutrons, he bombarded wax. Protons were released by the wax and Chadwick made measurements of the protons’ behavior
- awarded the Nobel Prize for Physics
- led the British team in the Manhattan Project
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Antoine Lavoisier
- lived from 1743 - 1794 in Paris, France
- named the elements carbon, hydrogen, and oxygen; discovered oxygen’s role in combustion and respiration
- established that water is a compound of hydrogen and oxygen
- discovered that sulfur is an element
- used a giant magnifying glass to focus the sun’s rays on a diamond; it disappeared
- had a great passion for accurate measurements – quantitative rather than qualitative science
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Joseph J. Thomson
- lived from 1856 - 1940 in Cheetham Hill, England
- created “Plum Pudding” model of the divisible atom: atoms consist of a large sphere of uniform positive charge embedded with smaller negatively charged particles (corpuscles)
- conducted experiment with cathode ray tubes that showed: a) 'canal rays' (positive) were different when different gases were used b) 'cathode rays' (negative) were always identical regardless of the nature of electrodes or gas used
- invented the mass spectrometer
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Marie Curie
- lived from 1867 - 1934 in Warsaw, Poland
- discovered two new chemical elements – radium and polonium
- investigated rays from uranium
- birth name: Maria Salomea Sklodowska
- carried out the first research into the treatment of tumors with radiation
- founder of the Curie Institutes, important medical research centers
- only person who’s ever won Nobel Prizes in both physics and chemistry
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Max Planck
- lived from 1858 - 1947 in Kiel, on the north coast of Germany
- birthed the quantum theory, accurately predicting wavelengths of light radiated by a black body
- experimented with electromagnetic spectrum emitted by hot objects
- composed classical music, had perfect pitch, played the cello, played the piano expertly, and had a beautiful singing voice
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Robert Millikan
- lived from 1868 - 1953 in Morrison, Illinois (USA)
- accurately determined the charge carried by an electron
- used the ‘falling-drop method’
- his religious and philosophic nature was evident from his lectures on the reconciliation of science and religion
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Ernest Rutherford
- lived from 1871 - 1937 in the village of Brightwater on New Zealand’s South Island
- discovered & named atomic nucleus, the proton, the alpha particle, & the beta particle
- discovered the concept of nuclear half-lives
- achieved the first deliberate transformation of one element into another
- conducted ‘gold foil’ experiment - used a sample of radium to provide a stream of alpha particles, which passed through the gold foil
- was J.J. Thomson’s student at the University of Cambridge, England
