A CHRONOLOGY OF THE ATOMIC VIEW OF NATURE
|c. 550 THALES
of Miletus (Greece, c. 640-546 B.C.) recorded the attractive properties
B.C. rubbed amber and of lodestone.
c. 450 LEUCIPPUS (Greece) proposed an atomic concept of matter.
c.400 DEMOCRITUS of Abdera (Greece, c. 460-357 B.C.), pupil of Leucippus, was the most
B.C. famous of the atomists in ancient times. He taught: "The only existing things are the
atoms and empty space; all else is mere opinion.
c. 335 ARISTOTLE (Greece, 384-322 B.C.) held that all matter was basically com posed of the
B.C. same continuous primordial stuff.
c.300 EPICURUS of Samos (Greece, c. 342-270 B.C.) founded a philosophical system based on
B.C. the atomism of Democritus.
c.300 ZENO of Cition (Greece, c. 336-264 B.C.) founded the Stoic school of philosophy which
B.C. held that matter, space, etc. were continuous.
c. 60 TITUS LUCRETIUS CARUS (Rome, c. 96-55 B.C.) attempted to formulate a rational
B.C. explanation of natural phenomena by extending the beliefs of Democritus and Epicurus.
His poem, De Rerum Natura, is the most complete record of Greek atomism extant.
The atomism of antiquity was primarily a system of metaphysics. The atomic view of
matter in the modern sense was barely introduced in its most elementary form by the
beginning of the 19th century.
c. 400 SAINT AUGUSTINE (Aurelius Augustinus) (North Africa, 354-430) was the first to report
that the forces exerted by rubbed amber and by lodestone are different properties.
c. 1600 WILLIAM GILBERT (England, 1540-1603) made the first detailed study of magnetism
and also showed that, in addition to amber, many other materials can be electrified.
1638 GALILEO GALILEI (Italy, 1564-1642) published Discorsi e Dimostrazioni
Matematiche intorno a due nuove Scienze attenti alla Mecanica e Movimenti locali
(Discourses and Mathematical Demonstrations concerning Two New Sciences
pertaining to Mechanics and Local Motions, usually contracted to Two New Sciences).
This account of Galileo's contributions to science establishes him as the founder of
dynamics. He was the first to make extensive use of the experimental
method to study natural phenomena. From his time on, induction from
experiment replaced the teleology of the scholastics as a guiding principle in the
organization of the natural sciences.
1650- ROBERT BOYLE (England, 1627-1691), ROBERT HOOKE (England, 1635 1703), and
1700 ISAAC NEWTON (England, 1642-1727) gave qualitative explanations of Boyle's law by
assuming a kinetic theory of gases.
1675 JEAN PICARD (France, 1620-1682) observed the luminous glow in the Torricellian vacuum
of a barometer produced by motion of the mercury when the instrument was carried from
place to place. << probably not related to Jean Luc Picard : ST-TNG >>
1675 ISAAC NEWTON (England) developed a corpuscular theory of light.
1676 OLE CHRISTENSEN ROEMER (Denmark, 1644-1710) was the first to show that the
velocity of light is finite. His conclusion was based on the variations of the time intervals
between consecutive eclipses of one of the moons of Jupiter during the course of the
revolution of the earth around the sun.
1678 CHRISTIAN HUYGENS (CHRISTIAAN HUYGHENS) (Netherlands, 1629-1695)
developed a wave theory of light in which light was regarded as composed of longitudinal
"pulses" consisting of compressions and rarefactions, similar to sound, in an extremely
thin, all-pervading medium which he called the aether. The concept that light is a periodic
wave motion was introduced in about 1750 by Leonard (Leonhard) Euler (Switzerland,
Germany, Russia, 1707-1783).
Not only did Huygens correctly account for the refraction of light by transparent bodies
by means of spherical emanations (wavelets), but also, by using both spherical and
spheroidal wavelets, he became the first one to explain double refraction, a phenomenon
that was discovered in 1669 by Erasmus Bartholinus (Denmark, 1625-1692).
1687 ISAAC NEWTON (England, 1642-1727) published Philosophiae Naturalis Principia
Mathematica (Mathematical Principles of Natural Philosophy) which contains the
fundamental laws of classical dynamics and the law of gravitation.The synthesis involved
in obtaining these laws is one of the greatest achievements of the human mind.
1705 FRANCIS HAUKSBEE (England, d. 1713) made a "powerful" electrostatic generator and
discovered the conditions for producing luminous electric discharges in gases.
1728 JAMES BRADLEY (England, 1693-1762) explained the aberration of light from stars by
taking the vector sum of the orbital velocity of the earth v and the free-space velocity of
light c, and showed that the angle of aberration was a function of the ratio of these
velocities, v/c. On this basis, he also showed that the revolution of the earth around the
sun correctly accounted for the observed cyclic change in the aberration of starlight. (The
Anti-Copernicans, still numerous in the first half of the 18th century, were unable to refute
this explanation of the change.) Bradley's work is the first of many instances that seemed
to show that the value of the velocity of light depends on the motion of the observer.
1731 STEPHEN GRAY (England, 1666/7-1736) discovered the conduction of electricity.
1734 CHARLES FRANCOIS de CISTERNAY DUFAY (France, 1698-1739) showed that there
are two kinds of electrification, resinous and vitreous, and then proposed a two-fluid
theory of electric discharge. He also found that the air in the vicinity of a hot body is
1738 DANIEL BERNOULLI (Switzerland, 1700-1782) was the first to devise a quantitative
kinetic theory of gases.
1745 EWALD JURGEN von KLEIST (Germany, d. 1748) and
PEITER VAN MUSSCHENBROEK (Netherlands, 1692-1761)
independently made the first capacitors, called Leyden jars.
1752 BENJAMIN FRANKLIN (USA, 1707-1790) experimentally verified the electrical
nature of lightning and introduced the one-fluid theory of flow of electricity -
from surplus of positive to deficiency or negative. His theory contained the
first clear statement of the law of conservation of electric charge.
1753 JOHN CANTON (England, 1718-1772) discovered the facts of electrostatic induction.
1766 HENRY CAVENDISH (England, 1731-1810) discovered hydrogen. Within the next score
of years he found the inverse square law of force action between electric charges and other
important laws of electricity but, because of excessive shyness, he withheld announcement
of his experiments. The great extent of his work was not known until James
Clerk Maxwell published Cavendish's papers in 1879.
1785 CHARLES AUGUSTIN COULOMB (France, 1736-1806) determined the law of force action
between electric charges.
1789 ANTOINE LAURENT LAVOISIER (France, 1734-1794) published a book containing a
well-founded concept of chemical elements and the verification of the law of conservation
of matter in chemical reactions.
1791 BRYAN HIGGINS (Ireland, 1737-1820) and WILLIAM HIGGINS (Ireland, c. 1769-1825)
reported the first of a series of experiments leading to the laws of chemical combination.
1799 JOSEPH Louis PROUST (France, Spain, 1754-1826) established the law of definite
proportions for chemical compounds.
1800 ALESSANDRO GUISEPPE ANTONIO ANASTASIO VOLTA (Italy, 1745-1827) made the
first voltaic pile (battery), based on his discovery of the fundamental conditions necessary
to produce the "animal electricity" that had first been observed in 1780 by Aloisio (or
Luigi) Galvani (Italy, 17371798).
1801 THOMAS YOUNG (England, 1773-1829) showed that his interference experiments verified
the wave theory of light.
1803 JOHN DALTON (England, 1766-1844) published the first of a series of papers
introducing atomic weights, establishing the law of multiple proportions, and founding
the atomic theory of matter.
1808 JOSEPH Louis GAY-LuSSAC (France, 1778-1850) discovered the law of combining volumes
1810- ETIENNE LOUIS MALUS (France, 1775-1812),
1875 DOMINIQUE FRANCOIS JEAN ARAGO (France, 1786-1853),
AUGUSTIN JEAN FRESNEL (France, 17881827),
JEAN BERNARD LEON FOUCAULT (France, 1819-1868),
HIPPOLYTE Louis FIZEAU (France, 1819-1896), and
MARIE ALFRED CORNU (France, 1841-1902) established conclusively, through many
experiments, especially in physical optics, that light is a transverse wave. Several of these
men made precise measurements of the velocity of light in various media. In 1818 Arago
found that- the refraction of a prism for starlight was the same for light incident in the
direction of the earth's orbital velocity v as for that coming in the opposite direction. This
unexpected null result was explained that same year by Fresnel's ether-drag theory, which
assumed partial ether entrainment in transparent media by an amount depending upon the
first power of v. This theory appeared fully verified by the measurements of the speed of
light in moving water by Fizeau in 1851 and, in 1871, by the observations of the aberration
of starlight with a water-filled telescope by GEORGE BIDDELL AIRY (England,
1811 LORENZO ROMANO AMADEO AVOGADRO (Italy, 1776-1856) introduced Avogadro's
hypothesis and differentiated between atoms and molecules.
1813 JONS JACOB BERZELIUS (Sweden, 1779-1848) introduced the present symbols for the
1815 WILLIAM PROUT (England, 1875-1850) proposed that all elements are composed of an
integral number of hydrogen atoms.
1815- JOSEPH FRAUNHOFER (Germany, 1787-1826) noted the spectral lines of several
1820 elements, obtained the first grating spectra, and observed the Fraunhofer (absorption)
lines in solar spectra.
1819 PIERRE LOUIS DULONG (France, 1785-1838) and
ALEXIS THERESE PETIT (France, 1791-1821) found the law of constancy of molar
specific heat capacities of elements.
1820 HANS CHRISTIAN OERSTED (Denmark, 1777-1851) discovered that an electric current
produces a magnetic field. This initiated the study of electromagnetism.
1821 THOMAS JOHANN SEEBECK (Russia, Germany, 1770-1831) discovered
1823 ANDRE MARIE AMPERE (France, 1775-1836) published his mathematical theory of
electromagnetism and the laws of magnetic field produced by currents. Some of these
laws were also discovered independently by JEAN BAPTISTE BIOT (France, 1774-1862)
and FELIX SAVART (France, 1791-1841).
1826 GEORG SIMON OHM (Germany, 1787-1854) discovered Ohm's law.
1827 ROBERT BROWN (England, 1773-1858) discovered Brownian movement.
1831 MICHAEL FARADAY (England, 1791-1867) and JOSEPH HENRY (USA, 1797-1878)
independently discovered electromagnetic induction.
1833 MICHAEL FARADAY (England) discovered the laws of electrolysisand
introduced the terms "anode" and "cathode."
1835 JOSEPH HENRY (USA) discovered self-induction and, in 1842, oscillatory electric
1842 JOHANN CHRISTIAN DOPPLER (Austria, 1803-1853) deduced a relation that showed
that the observed frequency of waves depends upon the relative motion of the source and
1842 JULIUS ROBERT MAYER (Germany, 1814-1878) calculated the mechanical equivalent
of heat theoretically from the specific heats of gases and vaguely proposed a law of
conservation of energy based on "Ex nihilo, nihil fit." His work was not published for
1843 JAMES PRESCOTT JOULE (England, 1814-1889) published the first of a series of reliable
experimental results that showed the constancy of the relation between mechanical energy
and heat-a basic step toward the law of conservation of energy.
1847 HERMANN LUDWIG FERDINAND VON HELMOLTZ (Germany, 1821-1894) proposed
the law of conservation of "force" (energy).
1848 WILLIAM THOMSON (Lord Kelvin, 1st Baron) (Ireland, Scotland, 18241907) introduced
1850 RUDOLPH JULIUS EMANUEL CLAUSIUS (Germany, 1822-1888) announced the second
law of thermodynamics. Lord Kelvin independently found the same law in 1852.
1850- AUGUST KARL KROENIG (Germany, 1822-1879),
1900 RUDOLPH JULIUS EMANUEL CLAUSIUS (Germany),
JAMES CLERK MAXWELL (Scotland, England, 1831-1879),
LUDWIG BOLTZMANN (Austria, 1844-1906), and
JOSIAH WILLARD GIBBS (USA, 1839-1903) developed the kinetic theory of gases
and founded statistical mechanics. Maxwell derived his speed distribution law in 1860,
Clausius introduced the concept of entropy in 1865, and Boltzmann related entropy to
thermodynamic probability in 1877.
1858 STANISLAO CANNIZZARO (Italy, 1826-1910) resolved the conflicting values of atomic
weights by clarifying the terms "atomic," "molecular," and "equivalent" weights.
1859 GUSTAV ROBERT KIRCHHOFF (Germany, 1824-1887) showed that the ratio of the
emittance to the absorptance for a given wavelength of radiation is the same for all
surfaces at the same temperature, and introduced the concept of cavity (Hohlraum) or
1859 HEINRICH GEISSLER (Germany, 1814-1879) and
JULIUS PLUECKER (Germany, 1801-1868) discovered the "rays"
(now called cathode rays) from the negative electrode in gaseous discharge tubes.
1863 JAMES ALEXANDER REINA NEWLANDS (England, 1837-1898) Stated the law of
octaves, a limited and elementary form of the periodic table of the elements.
1864 JAMES CLERK MAXWELL (Scotland, England, 1831-1879) wrote A Dynamical
Theory of the Electromagnetic Field, a paper synthesizing electricity,
magnetism, and light. This was probably the greatest work since
1865 JOSEPH LOSCHMIDT (Germany, 1821-1895) used the equations of the kinetic theory of
gases to make the first determination of Avogadro's number and of molecular diameters.
1869 DMITRI IVANOVICH MENDELEEV (Russia, 1834-1907) and
JULIUS LOTHAR MEYER (Germany, 1830-1895) independently introduced the periodic
table of the elements, a concise summary of years of experimental and theoretical
chemistry. The table is both mnemonic and heuristic.
1869 JOHANN WILHELM HITTORF (Germany, 1824-1914) observed the deflection of rays
from the cathode in a discharge tube, by means of a magnetic field.
1871 CROMWELL FLEETWOOD VARLEY (England, 1828-1883) found that the rays from
the cathode are negatively charged.
1876 EUGEN GOLDSTEIN (Germany, 1850-1930) introduced the name "cathode rays" and
began experiments leading eventually to the discovery of the positive counterpart,
Kanalstrahlen (channel or canal rays). In 1886 he suggested that the aurora is due to
cathode rays from the sun.
1877 WILLIAM RAMSAY (England, 1852-1916) and, independently,
JOSEPH DELSAULX (France, 1828-1891) and
IGNACE J. J. CARBONELLE (France, 1829-1889) advanced the first rather complete
qualitative explanation of Brownian movement by attributing it to molecular impact.
Some years later Ramsay discovered several of the noble gases, and made important
contributions to the study of radioactivity. He was awarded the Nobel prize for chemistry
1879 EDWIN HERBERT HALL (USA, 1855-1938) discovered the existence of a potential
difference between the opposite edges of a metal strip carrying a longitudinal electric
current, when the plane of the strip is set normal to a magnetic field. This is called the
1879 WILLIAM CROOKES (England, 1832-1919) began a long series of brilliant experiments
On the discharge of electricity through gases.
1879 JOSEF STEFAN (Austria, 1835-1893) announced Stefan's law, which gives the total
energy radiated by a blackbody. This was the first successful attempt to connect
absolute temperature and radiation.
1881 JULIUS ELSTER (Germany, 1854-1920) and HANS GEITEL (1855-1923) started a long,
systematic investigation of electrical effects produced by incandescent solids.
1883 THOMAS ALVA EDISON (USA, 1847-1931) discovered the Edison effect, the
emission of negative electricity from incandescent filaments in a vacuum.
1884 JOHANN JAKOB BALMER (Switzerland, 1825-1898) found an empirical wavelength
relation for a spectral series of hydrogen. This was the first series equation found for
1887 SVANTE AUGUST ARRHENIUS (Sweden, 1859-1927) conclusively established the ion
dissociation theory of electrolytes which grew from suggestions made by Clausius in 1857.
Arrhenius was awarded the Nobel prize for chemistry in 1903.
1887 ALBERT ABRAHAM MICHELSON (Germany, USA, 1852-1931) and
EDWARD WILLIAMS MORLEY (USA, 1838-1923) performed the first precision
experiment that showed that the earth has no ether drift. In a letter to Nature in 1879
Maxwell pointed out that evidence of ether drift had to be sought in second-order
effects-those depending on v2/c2. These are involved in interference methods. The first
trial by Michelson in 1881 gave inconclusive results. Michelson was awarded the Nobel
prize for physics in 1907.
1887 HEINRICH RUDOLPH HERTZ (Germany, 1857-1894) discovered the photoelectric
effect while verifying the existence of the electromagnetic waves predicted by Maxwell.
1888 WILHELM HALLWACHS (Germany, 1859-1922) showed that only negative charges are
emitted in the photoelectric effect.
1890 JOHANNES ROBERT RYDBERG (Sweden, 1854-1919) found an empirical wavelength
relation for complex series of spectral lines.
1891 JOHNSTONE STONEY (England, 1826-1911) introduced the name "electron" for an
elementary unit of negative charge in electrolysis.
1892 GEORGE FRANCIS FITZGERALD (Ireland, 1851-1901) and
HENDRIK ANTOON LORENTZ (Netherlands, 1853-1929) independently made the
ad hoc assumption of contraction of length to account for the null result of the
Michelson-Morley experiment. As Lorentz successively refined his electric theory of
matter to conform with the results of new experiments, he obtained the space and time
transformations later derived by Einstein. For later work Lorentz was awarded the Nobel
prize for physics jointly with P. Zeeman in 1902.
1893 WILHELM WIEN (Germany, 1864-1928) derived his blackbody radiation displacement
law. His blackbody radiation law was announced in 1896. He was awarded the Nobel
prize for physics in 1911.
1893 PHILIPP EDUARD ANTON VON LENARD (Hungary, Germany, 1862-1947)
investigated cathode rays by passing them through a Lenard window (thin-window) tube
into air. For this and later work he was awarded the Nobel prize for physics in 1905.
1895 JEAN BAPTISTE PERRIN (France, 1870-1942) demonstrated conclusively that cathode
rays are negatively charged. For this and later work he was awarded the Nobel prize for
physics in 1926.
1895 WILHELM CONRAD ROENTGEN (Germany, 1845-1923) discovered x-rays. He was
awarded the Nobel prize for physics in 1901.
1896 ANTOINE HENRI BECQUEREL (France, 1852-1908) discovered the radioactivity of
uranium. He was awarded the Nobel prize for physics jointly with the Curies in 1903.
1896 PIETER ZEEMAN (Netherlands, 1865-1943) observed the splitting of spectral lines
radiated by excited atoms in an intense magnetic field. The early theory of this effect was
derived by H. A. LORENTZ (Netherlands). They were jointly awarded the Nobel prize for
physics in 1902.
1896 OLIVER LODGE (England, 1851-1940) reported that, contrary to expectations, there was
no detectable ether drag on light passing between two large closely spaced disks of steel
rotating at enormous speeds even when the disks were strongly magnetized or electrified.
1897 JOSEPH JOHN THOMSON (England, 1856-1940) determined q/m for cathode rays. He
was awarded the Nobel prize for physics in 1906.
1897 ERNEST RUTHERFORD (Lord Rutherford of Nelson, 1st Baron)
(New Zealand, Canada, England, 1871-1937) showed that the radiation from
uranium was complex, consisting of "soft" (alpha) and "hard" (beta) rays.
He was awarded the Nobel prize for chemistry in 1908.
1898 PIERRE CURIE (France, 1859-1906) and
MARIE SKLODOWSKA CURIE (Poland, France, 1867-1934) isolated radium and
polonium. They were awarded the Nobel prize for physics jointly with H. Becquerel in
1903. Marie Curie was also awarded the Nobel prize for chemistry in 1911.
1899 HENRI BECQUEREL (France),
STEFAN MEYER (Austria, 1872-1949) and
EGON VON SCHWEIDLER (Austria, 1873-1948), and
FREDERICK OTTO GIESEL (Germany, 1852-1927) independently observed
the magnetic deflection of alpha and beta rays.
1899 JULIUS ELSTER (Germany) and HANS GEITEL (Germany) determined the law of
radioactive decay experimentally.
1899 PHILIPP LENARD (Germany) showed that photoelectric emission is due to electrons.
1899 J. J. THOMSON (England) showed that the Edison effect is due to electrons.
1899 OTTO LUMMER (Russia, Germany, 1860-1925) and
ERNST GEORG PRINGSHEIM (Germany, 1881-1917), and also
FERDINAND KURLBAUM (Germany, 1857-1927) and
HEINRICH RUBENS (Germany, 1865-1922) made precise measurements of the
intensity-wavelength distribution of blackbody radiation.
1900 JOHN WILLIAM STRUTT (Lord Rayleigh, 3rd Baron), (England, 1842-1919) announced
a blackbody radiation law. The derivation of this law was re-examined in collaboration
with JAMES HOPWOOD JEANS (England, 1877-1946) and, after publication in 1905,
became known as the RayleighJeans law. Rayleigh was awarded the Nobel prize for
physics in 1904.
1900 MAX KARL ERNST LUDWIG PLANCK (Germany, 1858-1947) introduced the
quantum theory of radiation-a revolutionary concept. He was awarded the Nobel prize
for physics in 1918.
1900 HENRI BECQUEREL (France) showed that beta rays are identical with cathode-ray
1900 PAUL VILLARD (France, 1860-1934) discovered gamma rays.
1902 PHILIPP LENARD (Germany) discovered photoelectric threshold frequency and also that
the kinetic energy of photoelectrons is independent of the intensity of the incident light.
1903 FREDERIC THOMAS TROUTON (Ireland, England, 1863-1922) and
H. R. NOBLE (England) were unable to observe any orienting torque on a suspended,
charged capacitor as predicted on the basis of an ether drift (a second-order effect).
1903 ERNEST RUTHERFORD (England) and
FREDERIC SODDY (England, 1877-1956) showed that every radioactive process is a
transmutation of elements. Soddy was awarded the Nobel prize for chemistry in 1921.
1903 WILLIAM CROOKES (England), and, independently,
JULIUS ELSTER (Germany) and HANS GEITEL (Germany) found that
the luminescence produced when alpha particles strike zinc sulfide consists of discrete
flashes of light of scintillations. This led to a method of counting individual alpha particles.
1904 WILLIAM RAMSAY (England) and FREDERIC SODDY (England) discovered the
remarkable occurrence of helium in all radium compounds.
1904 DEWITT BRISTOL BRACE (USA, 1859-1905) found no trace of the double refraction
predicted for an isotropic transparent body when it is rotated from parallel to the ether
drift to normal to it (a second-order effect). This type of experiment had been suggested
by the elder Lord Rayleigh.
1904 JOHN AMBROSE FLEMING (England, 1849-1945) applied the Edison effect to make the
first thermionic valve ("radio" tube).
1904 MARYAN VON SMOLUCHOWSKI (Austria, 1872-1919) proposed a statistical theory of
1905 ALBERT EINSTEIN (Germany, Switzerland, USA, 1879-1955) completed the statistical
theory of Brownian movement, introduced the quantum explanation of the photoelectric
effect, and announced the special theory of relativity. He was awarded the Nobel prize for
physics in 1921. The citation stated that the award was "for his contributions to
mathematical physics, and especially for his discovery of the law of the photoelectric
1905 EGON VON SCHWEIDLER (Austria) derived the law of radioactive decay from
probability theory-not obtainable from causality.
1906 OWEN WILLANS RICHARDSON (England, 1879-1959) began a long series of important
investigations on the emission of electricity from hot bodies (thermionic emission). He
was awarded the Nobel prize for physics in 1928.
1906 LEE DE FOREST (USA, 1873-1961) made the first audion (triode) by introducing a grid
into a Fleming valve.
1907- J. J. THOMSON (England) devised methods of positive-ray analysis. This was the
1912 beginning of mass spectroscopy.
1908 WALTER RITZ (Switzerland, 1878-1909) announced the combination principle for
computing the frequencies of spectral lines.
1908 LOUIS CARL HEINRICH FRIEDRICH PASCHEN (Germany, 1865-1947) experimentally
verified the existence of a spectral series of hydrogen in the near infrared predicted by
the Rydberg-Ritz relation.
1908 CHARLES GLOVER BARKLA (England, 1877-1944) discovered from absorption
experiments that the secondary x-rays of various elements are composed of groups
of characteristic x-rays which he called the K, L, and 117 radiations, and demonstrated
the polarization of x-rays. He was awarded the Nobel prize for physics in 1917.
1908 JEAN PERRIN (France) verified experimentally the several equations for Brownian
movement, obtained good values of Avogadro's number, and showed that equipartition
of energy held for small particles suspended in a stationary liquid.
1908 HERMANN MINKOWSKI (Lithuania, Germany, 1864-1909) developed a geometrical
interpretation of the special theory of relativity in which time and the three space
coordinates all had the same validity in a fourdimensional continuum.
1908- ALFRED HEINRICH BUCHERER (Germany, 1863-1927),
1910 E. HUPKA (Ger many), and
CHARLES EUGENE GUYE (France, 1866-1942) and
SIMON RATNOWSKY (Russia, Switzerland, 1884-1945) independently
made precision measurements of the mass of an electron as a function of its velocity.
The results verified the Lorentz-Einstein mass variation relation.
1909 GUGLIELMO MARCONI (Italy, 1874-1937) and
CARL FERDINAND BRAUN (Germany, 1850-1918) were jointly awarded the Nobel
prize for physics - the former for combining the basic knowledge about Hertzian waves
to produce wireless telegraphy, and the latter for the study, production, and use of
electrical oscillators. Braun also developed the Braun tube, called the "cathode-ray"
tube in the USA.
1909 ERNEST RUTHERFORD (England) and
THOMAS ROYDS (England, 18841955) showed that alpha particles are doubly
ionized helium atoms. 1909- T. WULF (France) observed the rate of leak of charge
from a highly 1910 insulated electroscope placed at the top of the Eiffel Tower, and
ALBERT GOCKEL (Switzerland, 1860-1927) studied the same effect in balloon ascents
up to 4500 meters. Both found the leakage rate greater than at the surface of the earth.
Their results were unexpected because the effect at ground level bad been ascribed to
local radioactivity of the soil.
1909- ROBERT ANDREWS MILLIKAN (USA, 1868-1953) established the law of multiple
1911 proportions for electric charges and made the first precise determination of the
electronic charge. He was awarded the Nobel prize for physics in 1923.
1910- VICTOR FRANZ HESS (Austria, USA, 1883-1964) and
1912 WERNER KOL HOERSTER (Austria, 1887-1945) discovered cosmic rays.
Hess was awarded the Nobel prize for physics jointly with C. D. Anderson in 1936.
1911 PETER JOSEPH WILHELM DEBYE (Netherlands, Switzerland, Germany, USA,
1884-1966) used the quantum theory to obtain a rather complete theory of specific heats,
and later applied the quantum concept to many problems in physical chemistry. He was
awarded the Nobel prize for chemistry in 1936.
1911- ERNEST RUTHERFORD (England),
1913 HANS GEIGER (Germany), and
ERNEST MARSDEN (England, b. 1889) showed that a nuclear model of the atom was
required to explain their experiments on alpha-particle scattering by thin metal foils.
1911 CHARLES THOMSON BEES WILSON (Scotland, England, 1869-1959) made the first
expansion cloud chamber. This is the most important device in nuclear physics. He was
awarded the Nobel prize for physics jointly with A. H. COMPTON in 1927.
1912 MAX FELIX THEODOR von LADE (Germany, 1879-1960) with
WALTER FRIEDRICH (Germany, b. 1883) and
PAUL C. M. KNIPPING (Germany, 1883-1935) established the wave nature of x-rays by
crystal diffraction. Laue was awarded the Nobel prize for physics in 1914.
1912 HANS GEIGER (Germany, 1882-1945) and JOHN MITCHELL NUTTALL (England,
1890-1958) obtained an empirical law relating the energy of an emitted alpha particle to
the disintegration constant of the parent nucleus.
1913 HANS GEIGER (Germany) published a detailed description of the pointdischarge counter
tube which was developed from a simpler form first made in 1908. This instrument was
greatly improved in 1928.
1913 FREDERICK SODDY (England) and
KASIMIR FAJANS (Poland, Germany, b. 1887) announced the laws of displacement in
the periodic table for elements undergoing radioactive decay. Soddy introduced the
1913 GEORGE CHARLES DE HEVESY (Hungary, Germany, Sweden, 1885-1966) and
FRITZ ADOLF PANETH (Austria, 1887-1959) used radium-D, an isotope of lead, to study
the solubility and the chemistry of lead compounds. This was the first use of an isotope as
a tracer element. Hevesy was awarded the Nobel prize for chemistry in 1943.
1913 NIELS HENRIK DAVID BOHR (Denmark, 1885-1962) developed the first successful
theory of atomic structure. He was awarded the Nobel prize for physics in 1922.
1913 JOHANNES STARK (Germany, 1874-1957) observed the splitting of spectral lines
radiated by excited atoms in an intense electric field. He was awarded the Nobel prize
for physics in 1919.
1913 JAMES FRANCK (Germany, USA, 1882-1964) and
GUSTAV HERTZ (Germany b. 1887)
supported the Bohr atomic theory with their measurements of ionization and resonance
potentials. They were awarded the Nobel prize for physics in 1925.
1913 WILLIAM HENRY BRAGG (England, 1862-1942) and son,
WILLIAM LAWRENCE BRAGG (Australia, England, b. 1890), studied x-ray
"reflection" from crystals and devised an x-ray spectrometer. They were awarded the
Nobel prize for physics in 1915.
1914 HENRY GWYN JEFFREY MOSELEY (England, 1884-1915) made x-ray spectrograms of
the elements and established the identity of the ordinal number of an element in the
periodic table with its nuclear charge (atomic number).
1914 KARL MANNE GEORG SIEGBAHN (Sweden, b. 1886) began a long series of pioneer
researches in the theory and application of precision x-ray spectroscopy. He was awarded
the Nobel prize for physics in 1924.
1915 ARNOLD JOHANNES WILHELM SOMMERFELD (Germany, 1868-1951) improved
the Bohr atomic model by introducing elliptical orbits and relativistic effects.
1915 WILLIAM DUANE (USA, 1872-1935) and
FRANKLIN LIVINGSTON HUNT (USA, b. 1883) showed that the short-wavelength
limit of emitted xradiation is determined by the quantum theory.
1915 ALBERT EINSTEIN (Germany, USA) announced the general theory of relativity. It
considers the observations of phenomena on accelerated reference frames.
1916 R. A. MILLIKAN (USA) experimentally verified Einstein's photoelectric equation.
1916 P. J. W. DEBYE (Netherlands, Switzerland, USA)
PAUL SCHERRER (Switzerland, b. 1890), and, independently,
ALBERT WALLACE HULL (USA, 1880-1966) obtained the first x-ray powder
1916 THEODORE LYMAN (USA, 1874-1954) found the Lyman series lines predicted by
Bohr's theory of the hydrogen atom. Lyman had observed at least one of these lines
as early as 1906.
1919 ERNEST RUTHERFORD (England) produced hydrogen and oxygen by alpha-particle
bombardment of nitrogen, the first "man-made" transmutation of an element.
1919 FRANCIS WILLIAM ASTON (England, 1877-1945) made the first highprecision
determinations of isotopic masses. He was awarded the Nobel prize for chemistry in 1922.
1919 The observations made during a total solar eclipse in this year by an expedition from the
Royal Astronomical Society and the Royal Society of London confirmed the deviation of
starlight in the gravitational field of the sun as predicted by the general theory of
relativity. The strongest support for this theory came later from the agreement between
the calculated and observed values of the precession of the perihelion of Mercury.
1921 OTTO STERN (Germany, USA, b. 1888) and
WALTER GERLACH (Germany, b. 1889) verified the space quantization of silver atoms
in a magnetic field and measured their magnetic moment. Stern was awarded the Nobel
prize for physics in 1943.
1923 ARTHUR HOLLY COMPTON (USA, 1892-1962) discovered the Compton effect, which
showed that a photon has momentum. He was awarded the Nobel prize for physics jointly
with C. T. R. WILSON in 1927.
1924 EDWARD VICTOR APPLETON (England, 1892-1965) began a series of experiments that
established the existence and properties of ionized layers in the high atmosphere. Such
layers had been postulated in 1902 by ARTHUR EDWIN KENNELLY (India, USA,
1861-1939) and, independently, by OLIVER HEAVISIDE (England, 1850-1925) to
account for-long-distance wireless telegraphy. Appleton was awarded the Nobel prize
for physics in 1947.
1924 SATYENDRANATH BOSE (India, b. 1894) and
A. EINSTEIN independently developed the statistics "obeyed" by bosons, a
collective name for photons, nuclei of even mass number, and certain other particles.
1924 Louis VICTOR, DUC DE BROGLIE (France, b. 1892) introduced the concept of
de Broglie waves, the beginning of the wave theory of matter. He was awarded the
Nobel prize for physics in 1929.
1925 WALTER M. ELSASSER (Germany, USA, b. 1904) predicted from de Broglie theory that
electrons could be diffracted by crystals.
1925 CHARLES DRUMMOND ELLIS (England, b. 1895) and
W. A. WOOSTER (England) established that in a number of elements the emission of
either an alpha or a beta particle precedes the radiation of gamma rays, and thus the
latter should be associated with the daughter product, not with the parent.
1925 PIERRE VICTOR AUGER (France, b. 1899) discovered a type of energy transition in
which an atom goes from a higher to a lower state by ejecting one of its own electrons,
without the emission of electromagnetic radiation.
1925 GEORGE EUGENE UHLENBECK (Java, Netherlands, USA, b. 1900) and
SAMUEL ABRAHAM GOUDSMIT (Netherlands, USA, b. 1902) introduced spin
and magnetic moment of the electron into atomic theory.
1925 WOLFGANG PAULI (Austria, Switzerland, 1900-1958) announced the exclusion principle.
He was awarded the Nobel prize for physics in 1945.
1925 PATRICK MAYNARD STUART BLACKETT (England, b. 1897) obtained the first
cloud-chamber tracks of the induced transmutation of nitrogen and of other elements, and
later made many cosmic-ray studies. He was awarded the Nobel prize for physics in 1948.
1925 MAX BORN (Bermany, b. 1882),
WERNER KARL HEISENBERG (Germany, b. 1901), and
PASCUAL JORDAN (Germany, b. 1902) developed quantum mechanics. Later, Born
originated the statistical interpretation of wave mechanics, and he was awarded the
Nobel prize for physics jointly with W. BOTHE in 1954.
1926 ERWIN SCHROEDINGER (Austria, Ireland, 1887-1961) proposed the wavemechanical
theory of the hydrogen atom. He was awarded the Nobel prize for physics jointly with
P. A. M. DIRAC in 1933.
1926 ENRICO FERMI (Italy, USA, 1901-1954) and
PAUL ADRIEN MAURICE DIRAC (England, b. 1902) independently developed the
statistics "obeyed" by fermions, a collective name for nuclei of odd mass number, some
particles, and electrons, particularly the electron gas in a conductor. Each was awarded
the Nobel prize for work listed later in this chronology.
1926 EUGENE PAUL WIGNER (Hungary, USA, b. 1902) published the first of a long series of
important papers on the application of group theory in quantum mechanics. He was
awarded the Nobel prize for physics jointly with MARIA MAYER and J. H. D. JENSEN
1927 WERNER HEISENBERG (Germany) announced the "Unbestimmtheit Prinzip"
(indeterminacy or uncertainty principle). He was awarded the Nobel prize for physics
1927 CLINTON JOSEPH DAVISSON (USA, 1881-1958), and
LESTER HALBERT GERMER (USA, b. 1896) obtained electron diffraction from single
crystals, and GEORGE PAGET THOMSON (England, b. 1892) obtained powder diffraction
patterns using electrons. Their work verified the existence of de Broglie waves. Davisson
and Thomson were awarded the Nobel prize for physics in 1937.
1928 EDWARD UHLER CONDON (USA, b. 1902) and
RONALD WILFRID GURNEY (England, USA, 1898-1953) and, independently,
GEORGE GAMOW (Russia, USA, b. 1904) solved the nuclear problem of alpha-particle
emission by means of wave mechanics and derived the Geiger-Nuttall law.
1928 P. A. M. DIRAC (England) developed relativistic quantum mechanics and predicted the
existence of the positron. He was awarded the Nobel prize for physics jointly with
E. SCHROEDINGER in 1933.
1928 CHANDRASEKHARA VENKATA RAMAN (India, b. 1888) discovered the Raman effect.
This is the presence, in light scattered from molecules, of frequencies differing from that
of the incident light by amounts characteristic of the scattering substance and independent
of the incident frequency. He was awarded the Nobel prize for physics in 1930.
1928 DMITRI VLADIMIROVICH SKOBELTSYN (Russia, b. 1892) obtained the first
cloud-chamber photographs of cosmic rays. These showed that the rays either were, or
produced, many charged, high-energy particles.
1928 HANS GEIGER (Germany) and
W. MUELLER (Germany) developed the Geiger point counter (1913) into a greatly
improved form, called the Geiger-Mueller counter.
1928 WALTHER WILHELM GEORG FRANZ BOTHE (Germany, 1891-1957) and
W. KOLHOERSTER (Austria) applied G-M tubes to make coincidence counters and other
ingenious devices for cosmic-ray study. Bothe was awarded the Nobel prize for physics
jointly with M. BORN in 1954.
1929 OTTO STERN (Germany) obtained crystal diffraction of a beam of helium atoms.
1930 W. BOTHE (Germany) and H. BECKER (Germany) observed a puzzling penetrating
"radiation" from beryllium bombarded with alpha particles.
1930 JACOB CLAY (Netherlands, b. 1882) discovered that cosmic-ray intensity decreased in
going toward the geomagnetic equator. This latitude effect was investigated exhaustively
by A. H. COMPTON, R. A. MILLIKAN, and others.
1930- FREDRIK CARL MUELERTZ STOERMER (Norway, 1874-1957) applied his 1934
theory of the motion of charged particles in the magnetic field of the earth, originally
developed to account for the aurora borealis, to cosmic rays. This theory of the cause of
geomagnetic effects was greatly expanded in 1933 by GEORGES LEMAITRE (Belgium,
1894-1966) and MANUEL SANDOVAL VALLARTA (Mexico, b. 1899). Further
theoretical work was done by WILLIAM FRANCIS GRAY SWANN (England, USA,
1884-1962) and others.
1930- IRA FORRY ZARTMAN (USA, b. 1899) and C. C. Ko (China, USA) experi1933 mentally
verified the Maxwell distribution law of molecular speeds.
1931 THOMAS HOPE JOHNSON (USA, b. 1899) obtained crystal diffraction of a beam of
1931 ROBERT JEMISON VAN DE GRAAFF (USA, 1901-1967) constructed the first reliable,
high-voltage, electrostatic generator for nuclear research.
1931 WOLFGANG PAULI (Austria, Switzerland) proposed a hypothesis of betadecay processes
postulating that a "new," small, neutral particle was emitted simultaneously with the
1931 HAROLD CLAYTON UREY (USA, b. 1893),
FERDINAND GRAFT BRICKWEDDE (USA, b. 1903), and
GEORGE MOSELEY MURPHY (USA, b. 1903) discovered deuterium and made the first
heavy water. Urey was awarded the Nobel prize for chemistry in 1934.
1932 ROY JAMES KENNEDY (USA, b. 1897) and
EDWARD MOULTON THORNDIKE (USA, b. 1905) sought to detect the ether drift with
a very stable and refined form of interferometer having arms of unequal length. Both the
length and the time transformations of the special theory of relativity had to be used to
account for the null result.
1932 ERNEST ORLANDO LAWRENCE (USA, 1901-1958) and
MILTON STANLEY LIVINGSTON (USA, b. 1905) made the first cyclotron.
Lawrence was awarded the Nobel prize for physics in 1939.
1932 JOHN DOUGLAS COCKCROFT (England, b. 1897) and
ERNEST, THOMAS SINTON WALTON (Ireland, b. 1903) accomplished the
transmutation of lithium by bombarding it with high-energy protons, and so obtained the
first direct verification of Einstein's law of mass-energy equivalence. This was also the
first time a high-voltage accelerator was used successfully to produce a nuclear reaction.
They were awarded the Nobel prize for physics in 1951.
1932 JAMES CHADWICK (England, b. 1891) discovered the neutron. This particle
accounted for Bothe and Becker's penetrating "radiation." He was awarded the Nobel
prize for physics in 1935.
1932 BRUNO BENEDETTO Rossi (Italy, USA, b. 1905) found an initial increase with thickness
in the cosmic-ray intensity "transmitted" by an absorber and explained this by cosmic-ray
showers. A transition to decreasing intensities was observed beyond a certain thickness.
1932 CARL DAVID ANDERSON (USA, b. 1905) discovered the positron during cosmic-ray
research. He was awarded the Nobel prize for physics jointly with V. F. HESS in 1936.
1933 P. M. S. BLACKETT (England) and G. P. S. OCCHIALINI (England) obtained the first
cloud-chamber photographs of electron-positron pair production.
1933 JEAN VALENTIN THIBAUD (France, 1901-1960) and FREDERIC JOLIOT (France,
1900-1958) observed the radiation produced by electron-positron annihilation. They also
showed that the mass of the positron is equal to that of the electron.
1933 T. H. JOHNSON (USA) and
JABEZ CURRY STREET (USA, b. 1906) observed that the cosmic-ray intensity from the
west exceeded that from the east. This east-west asymmetry shows that there is an excess
of positively charged particles in the primary cosmic-ray beam.
1934 PAVEL ALEKSEJEVIC CHERENKOV (Russia, b. 1904) observed the weak, bluish glow
in transparent substances when irradiated with high-energy beta particles. The theory of
this Cherenkov radiation was given by IGOR JEVGENEVIC TAMM (Russia, b. 1895)
and ILYA MICHAJLOVIC FRANK (Russia, b. 1908) three years later. These three
scientists were jointly awarded the Nobel prize for physics in 1958.
1934 S. MOHOROVICIC (Yugoslavia) predicted the existence of a transitory non-nuclear
"element" (later called positronium) preceding electronpositron annihilation.
1934 IRENE JOLIOT-CURIE (France, 1897-1956) and FREDERIC JOLIOT (France)
discovered artificial (induced) radioactivity. They were awarded the Nobel prize for
chemistry in 1935.
1934 ENRICO FERMI (Italy, USA) developed Pauli's theory of beta decay and named the
"new" particle the neutrino (little neutron). It is postulated in Fermi's theory that the
neutron is radioactive, disintegrating into a proton with the formation of an electron and
a neutrino just before beta emission. He also began a series of experiments in
collaboration with EDUARDO AMALDI (Italy, b. 1908), OSCAR D'AGOSTINO (Italy),
FRANCO RASETTI (Italy, USA, b. 1901) and EMILIO GINO SEGRE (Italy, USA, b.
1905) to produce transuranic elements by irradiating uranium with neutrons. They were
granted a patent on the graphite moderator in 1955. Fermi was awarded the Nobel prize
for physics in 1938.
1935- ISIDOR ISAAC RABI (Austria, USA, b. 1898) made precise determinations of nuclear
1939 magnetic moments in beams of atoms by his radiofrequency resonance method. He was
awarded the Nobel prize for physics in 1944.
1935 HIDEKI YUKAWA (Japan, b. 1907) announced his theory of nuclear binding forces
involving the postulate of a particle having a mass intermediate between that of the
electron and the proton. He was awarded the Nobel prize for physics in 1949.
1936 C. D. ANDERSON (USA) and SETH HENRY NEDDERMEYER (USA, b. 1907)
discovered, during cosmic-ray research, a particle of the type postulated by Yukawa.
They called it the "mesotron" (later changed to "meson").
1936 MARIETTA BLAU (Austria, b. 1894) was the first to use nuclear track plates.
1937 NIELS BOHR (Denmark) introduced the liquid-drop model of the nucleus.
1938 IRENE JOLIOT-CURIE (France) and
PAVLE SAVITCH (Yugoslavia, b. 1908) found indications of the existence of lanthanum
in uranium after it was irradiated with neutrons.
1938 OTTO HAHN (Germany, b. 1879) and
FRITZ STRASSMANN (Germany, b. 1902) discovered that bombarding uranium with
neutrons produces alkali earth elements. Hahn was awarded the Nobel prize for
chemistry in 1944.
1939 LISE MEITNER (Austria, Germany, Sweden, b. 1878) and
OTTO RICHARD FRISCH (Austria, Germany, England, b. 1904) proposed nuclear
splitting to explain Hahn's results on the disintegration of uranium by- neutrons and
predicted the release of an enormous amount of energy per fission.
1939 NIELS BOHR (Denmark) and
JOHN ARCHIBALD WHEELER (USA, b. 1911) developed the theory of nuclear fission.
1939 HANS ALBRECHT BETHE (Germany, USA, b. 1906) and
CARL FRIEDRICH VON WEIZSAECKER (Germany, b. 1912) independently proposed
two sets of nuclear reactions to account for stellar energies: the carbon cycle and the
1940 JOHN RAY DUNNING (USA, b. 1907),
EUGENE THEODORE BOOTH (USA, b. 1912), and
ARISTID V. GROSSE (Russia, USA, b. 1905) showed that it is U235, the less abundant
isotope of uranium, that is fissioned by slow neutrons.
1940 Louis LEPRINCE-RINGUET (France, b. 1901) obtained the first cloudchamber photograph
of a meson-electron collision, from which the mass of the meson could be deduced.
1940 DONALD WILLIAM KERST (USA, b. 1911) made the first betatron, an induction type
1940 EDWIN MATTISON MCMILLAN (USA, b. 1907) and
PHILIP HAGUE ABELSON (USA, b. 1913) produced the first transuranic element,
GLENN THEODORE SEABORG (USA, b. 1912),
EDWIN MATTISON MCMILLAN (USA),
JOSEPH WILLIAM KENNEDY (USA, b. 1917), and
ARTHUR CHARLES WAHL (USA, b. 1917) prepared the second transuranic element,
plutonium. MCMILLAN and SEABORG were awarded the Nobel prize for chemistry
1942 ENRICO FERMI (Italy, USA),
LEO SZILARD (Hungary, Germany, USA, 1898-1964), and associates
built the first successful self-sustaining fission reactor. It was first put into operation on
December 2 and operated at a power level of one-half watt. It was located in Chicago,
1945 J. ROBERT OPPENHEIMER (USA, b. 1904), then Director of the Los Alamos Scientific
Laboratory, and the many scientists engaged there in a "crash" program of basic nuclear
research and development saw the culmination of their work in the detonation of the first
nuclear bomb at Almagordo, New Mexico, on July 16.
1945 E. M. MCMILLAN (USA) and
VLADIMIR IOSIFOVICH VEKSLER (Russia, 1907-1966) independently proposed the
principle of the synchrotron, the type of accelerator which produces very high-energy
particles, as in the Cosmotron, Bevatron, etc.
1946 FELIX BLOCH (Switzerland, USA, b. 1905) devised the magnetic induction method and,
EDWARD MILLS PURCELL (USA, b. 1912) originated the magnetic resonance
absorption method for determining nuclear magnetic moments, using liquids or solids in
bulk (not beams). This led to the nuclear resonance spectrometer. They were awarded
the Nobel prize for physics in 1952.
1947 POLYKARP KUSCH (Germany, USA, b. 1911) made high-precision determinations of the
magnetic moment of the electron and found a small but theoretically significant difference
between the predicted value and the experimental results. Kusch was awarded the Nobel
prize for physics jointly with W. R. LAMB in 1955.
1947 WILLIS EUGENE LAMB, JR., (USA, b. 1913) and
ROBERT E. RETHERFORD (USA) observed, during the course of spectral
measurements of the fine structure of hydrogen in the microwave region, a small
displacement (the "Lamb shift") of an energy level from its theoretical position as
predicted by Dirac's quantum theory of the electron.Lamb was awarded the Nobel prize
for physics jointly with P. KUSCH in 1955.
1947 H. A. BETHE (Germany, USA) and, independently,
JULIAN SEYMOUR SCHWINGER (USA, b. 1918) explained the discrepancies found
by KUSCH and by LAMB as resulting from an interaction of electrons with the radiation
field. Schwinger was awarded the Nobel prize for physics jointly with R. P. FEYNMAN
and S. TOMONAGA In 1965.
1947 HARTMUT PAUL KALLMANN (Germany, USA, b. 1896) and, independently,
JOHN WESLEY COLTMAN (USA, b. 1915) and
FITZ-HUGH BALL MARSHALL (USA, b. 1912) developed scintillation counters.
1947 CECIL FRANK POWELL (England, b. 1903),
G. P. S. OCCHIALINI (England), and
CESARE MANSUETO GIULIO LATTES (Brazil, England, b. 1924)
discovered the pi-meson. Powell was awarded the Nobel prize for physics in 1950.
1947 GEORGE DIXON ROCHESTER (England, b. 1908) and
CLIFFORD CHARLES BUTLER (England, b. 1922)
discovered V-particles and hyperons.
1948 EUGENE GARDNER (USA, 1913-1950) and
C. M. G. LATTES (Brazil, England, USA) were the first to produce mesons in the
1948- WILLARD FRANK LIBBY (USA, b. 1908) and collaborators developed the
1950 techniques of radiocarbon dating. He was awarded the Nobel prize for chemistry in 1960.
1949 MARIA GOEPPERT MAYER (Germany, USA, b. 1906) and, independently,
OTTO HAXEL (Germany, b. 1909),
JOHANNES HANS DANIEL JENSEN (Germany, b. 1907), and
HANS EDWARD SUESS (Austria, Germany, USA, b. 1909) developed the shell theory
of the nucleus, which assumes a spherical distribution of nucleons. Mayer and Jensen
were awarded the Nobel prize for physics jointly with E. P. WIGNER in 1963.
1950 ARTHUR HAWLEY SNELL (Canada, USA, b. 1911) and associates
at the Oak Ridge National Laboratory and
JOHN MICHAEL ROBSON (England, Canada, b. 1920) and his associates
at the Chalk River Laboratory experimentally verified that the free neutron
1950 Scientists began intensified research on light-element fusion reactions.
1951 MARTIN DEUTSCH (Austria, USA, b. 1917) experimentally confirmed the prediction of
the existence of positronium.
1952 Brookhaven National Laboratory was the first to achieve the acceleration of particles to
the giga-electron-volt energy range: 2.3-Gev protons.
1952 AAGE BOHR (Denmark, b. 1922) and
BEN ROY MOTTELSON (Denmark b. 1926) developed the unified (collective) shell
model of the nucleus, which assumes a nonspherical nuclear core. The possibility of a
distorted core had been suggested in 1950 by LEO JAMES RAINWATER (USA, b. 1917).
1952 DONALD ARTHUR GLASER (USA, b. 1926) made the first bubble chamber. He was
awarded the Nobel prize for physics in 1960.
1952 The first large-scale, terrestrial thermonuclear reaction was produced when a "hydrogen
fusion device" was tested at Einewetok atoll on November 1.
1953 MURRAY GELL-MANN (USA, b. 1929) introduced the strangeness numbers for nucleons,
mesons, and hyperons, and found that strangeness is conserved in strong interactions.
1953 ROBERT HOFSTADTER (USA, b. 1915) and collaborators started a series of experiments
on the scattering of high-energy electrons by atoms. The results led to the determination
of the charge distribution and structure of nuclei and nucleons. Hofstadter was awarded
the Nobel prize for physics jointly with R. L. Mossbauer in 1961.
1954 JAMES POWER GORDON (USA, b. 1928),
H. J. ZEIGER (USA, b. 1925) and
CHARLES HARD TOWNES (USA, b. 1915) made the first maser [molecular (formerly,
microwave) amplification by stimulated emission of radiation]. In this device, many
molecules which have been put into high energy states are induced to emit their energy
as radiation by a weak incoming signal of the same frequency. Townes was awarded the
Nobel prize for physics jointly with N. BASOV and A. PROKHORV in 1964.
1955 OWEN CHAMBERLAIN (USA, b. 1920),
EMILIO GINO SEGRE (Italy, USA, b. 1905),
CLYDE EDWARD WIEGAND (USA, b. 1915), and
THOMAS JOHN YPSILANTIS (USA, b. 1928) created proton-antiproton pairs.
Chamberlain and Segre were awarded the Nobel prize for physics in 1959.
1956 Luis WALTER ALVAREZ (USA, b. 1911) and collaborators accomplished cold fusion of
deuterium with the negative mu-meson as a catalyst.
1956 JOHN BARDEEN (USA, b. 1908),
WALTER HOUSER BRATTAIN (China, USA, b. 1902), and
WILLIAM SHOCKLEY (England, USA, b. 1910) were awarded the Nobel prize for physics
in recognition of their work in theory of the solid state, particularly semiconductors.
1956 FREDERIC REINES (USA, b. 1915) and
CLYDE LORRAIN COWAN, JR. (USA, b. 1919) and collaborators experimentally
confirmed the existence of the neutrino.
1956 The world's first full-scale nuclear power plant was put into operation on October 17 at
Calder Hall, England. The gas-cooled reactors develop 360 megawatts of thermal power
to deliver 78 megawatts of electrical power.
1956 TSUNG DAO LEE (CHINA, USA, b. 1926) and
CHEN NING YANG (China, USA, b. 1922) deduced theoretically that hre law of
conservation of parity (the invariance of spatial inversion) is invalid for weak interactions.
They were awarded the Nobel prize for physics in 1957.
1956 CHINN-SHIUNG Wu (China, USA, b. 1915) and collaborators performed the first
experiment that demonstrated the violation of conservation of parity. They observed the
beta emission from Co^60 at very low temperatures.
1956 Hoosick , N.Y. Dist. #2 Sends five onto High School, inc. AJD
1957 JOHN BARDEEN (USA),
LEON N. COOPER (USA, b. 1930) and
JOHN ROBERT SCHRIEFFER (USA, b. 1931) announced the first comprehensive
theory of superconductivity.
1958 C. H. TOWNES (USA),
JOHN PERRY CEDARHOLM (USA, b. 1927),
GEORGE FRANCIS BLAND (USA, b. 1927), and
BYRON LUTHER HAVENS (USA, b. 1914) employed maser beams in the most precise
ether-drift experiment yet performed. The results showed that if the effect exists, it is less
than one-thousandth of the earth's orbital speed or less than one ten-millionth of the speed
of light. The precision in the comparison of the frequencies of the masers was about one
part in a million million.
1958 RUDOLPH L. MOSSBAUER (Germany, b. 1929) predicted and found an extremely small
frequency spread in the emission of low-energy gamma rays from nuclei bound in a crystal
lattice. This effect results from giving the gamma-ray recoil momentum to the whole
lattice instead of to an individual nucleus. The effect provides a very high-precision
frequency standard suitable for testing several predictions of the special and general
theories of relativity. He was awarded the Nobel prize for physics jointly with
R. HOFSTADTER in 1961.
1959 JAMES ALFRED VAN ALLEN (USA, b. 1914) showed from the data obtained from
instruments carried by artificial satellites that the earth is encircled by two zones, called
VAN ALLEN radiation belts, of high-energy charged particles which are trapped by the
earth's magnetic field.
1960 Drury HS, No. Adams, MA Graduates over 200, inc. AJD
1960 THEODORE HAROLD MAIMAN (USA, b. 1927) made the first ruby laser.
1960 ALI JAVAN (Iran, USA, b. 1926) made the first helium-neon laser.
1960 VERNON WILLARD HUGHES (USA, b. 1921),
D. W. McCOLM, KLAUS OTTO Ziock (Germany, USA, b. 1925) and
R. PREPOST made and studied muonium,a short-lived atom having a positive mu-meson
nucleus and an orbiting electron.
1962 B. D. JOSEPHSON (England) discovered and theoretically analyzed a number of
unexpected phenomena occurring at a "Josephson junction," an arrangement consisting
of two superconductors separated by a very thin layer of insulating material.
1964 MA State College at No. Adams unleashes .LT. 30 Sci-Math's, inc. AJD
1965 JEROME V. V. KASPER and GEORGE CLAUDE PIMENTEL (USA, b. 1922) made the
first chemical laser, a device in which pumping energy is supplied by chemical reactions
instead of by an external source of power.