Central Events in Physics

Murray, C.A. (2003) Human accomplishment the pursuit of excellence in the Arts and Sciences, 800 B.C. to 1950. HarperCollins Publishers.

Year	Country	Event
260 BCE	Greece	Archimedes discovers the principle of the lever.
260 BCE	Greece	Archimedes discovers the principle of buoyancy, leading to the concept of specific gravity.
1025	Arabia	Alhazen’s Opticae Thesaurus discusses the properties of lenses, the nature of refraction and reflection, and correctly states that the object seen is the source of light rays.
1269	France	Peter Peregrinus’s Epistola de Magnete identifies magnetic poles, also representing an early, unsophisticated use of the experimental method.
1583	Italy	Galileo discovers that a pendulum’s period of oscillation is independent of its amplitude.
1583	Netherlands	Simon Stevin introduces the theory of static equilibrium, founding hydrostatics.
1586	Netherlands	Simon Stevin presents evidence that falling bodies fall at the same rate.
1589	Italy	Galileo’s tests of falling bodies represent a landmark use of experimental data.
1592	Italy	Galileo invents the thermometer (precisely, barothermometer).
1600	England	William Gilbert’s De Magnete, Magnetisque Corporibus, et de Magno Magnete Tellure describes the magnetic properties of the earth and founds the scientific study of electricity.
1604	Italy	Galileo discovers that a free-falling body increases its distance as the square of the time, a pioneering mathematization of a physical phenomenon.
1609	Netherlands	Zacharias Jansen and Hans Lippershey invent the compound microscope.
1621	Netherlands	Willebrord Snell discovers Snell’s Law for computing the refraction of light, later discovered independently by Descartes.
1638	Italy	Galileo’s Discoursi e Dimostrazioiii Matematiche, Intorno d Due Nuove Scienze founds modern mechanics.
1643	Italy	Evangelista Torricelli invents the barometer in the process of discovering air pressure.
1643	Italy	Evangelista Torricelli creates the first (near) vacuum known to science.
1645	Germany	Otto von Guericke discovers that, in a vacuum, sound does not travel, fire is extinguished, and animals stop breathing.
1648	France	Blaise Pascal states Pascal’s principle, that pressure on an enclosed fluid is transmitted without reduction throughout the fluid, founding hydraulics.
1650	Germany	Otto Von Guericke demonstrates the force of air pressure, using teams of horses to try to pull apart metal hemispheres held together by a partial vacuum.
1665	England	Robert Hooke’s Micrographia introduces the first major challenge to the concept of light as a stream of particles, arguing instead that light is a vibration.
1665	Italy	Francesco Grimaldi gives the first major account of light diffraction and interference.
1669	Denmark	Erasmus Bartholin describes double refraction, the apparent doubling of images when seen through a crystal.
1670	Netherlands	Christiaan Huygens develops a wave theory of light, published in 1690.
1672	England	Isaac Newton describes the light spectrum, and discovers that white light is made from a mixture of colors.
1675	France	Ole Romer deduces that light has a speed and calculates an approximation of it (put at 141,000 miles per second).
1687	England	Isaac Newton’s Philosophiae Naturalis Principia Mathematica states the law of universal gravitation.
1687	England	Isaac Newton’s Principia states the laws of motion.
1687	England	Isaac Newton’s Principia predicts that the shape of the earth is nonspherical, based on the finding that gravity at Cayenne is less than that at Paris.
1701	France	Joseph Sauveur describes the production of tones by the vibration of strings and coins the word acoustic.
1704	England	Isaac Newton’s Opticks: A Treatise of the Reflections, Refractions, Inflections, and Colours of Light discusses optical phenomena, including the suggestion that light is particulate in nature.
1714	Netherlands	Daniel Fahrenheit invents the Fahrenheit scale.
1714	Netherlands	Daniel Fahrenheit invents the mercury thermometer, the first accurate thermometer.
1728	England	James Bradley discovers the aberration of starlight, leading to a better measure of the speed of light and providing evidence for a heliocentric solar system.
1733	France	Charles DuFay discovers that there are two types of static electric charges and that like charges repel each other while unlike charges attract, linking electricity to magnetism.
1738	Switzerland	Daniel Bernoulli’s Hydrodynatnica states Bernoulli’s Principle and founds the mathematical study of fluid flow and the kinetic theory of gases.
1742	Sweden	Anders Celsius invents the Celsius scale
1745	Germany, Netherlands	Ewald von Kleist and Pieter van Musschenbroek independently invent a practical device for storing an electric charge, the Leyden jar.
1748	France	Jean Nollet discovers osmosis, the passage of a solution through a semi-permeable membrane separating two solutions with different concentrations.
1752	USA	Benjamin Franklin discovers that lightning is a form of electricity.
1762	Scotland	Joseph Black develops the concept of latent heat, the quantity of heat absorbed or released when a substance changes its physical phase at constant temperature.
1787	France	Jacques Charles demonstrates that different gases expand by the same amount for a given rise in temperature, known both as Charles’s law and Gay-Lussac’s law (Joseph Gay-Lussac is the first to publish, in 1802. The relationship was first stated a century earlier by Guillaume Amontons, then forgotten).
1798	England	Henry Cavendish and Nevil Maskelyne measure the gravitational constant, leading to an accurate estimate of the mass of the earth.
1798	Germany	Benjamin Thompson (Count Rumford) demonstrates that heat is a form of motion (energy) rather than a substance.
1800	England	William Herschel discovers infrared radiation, and that invisible light beyond the red produces the most heat.
1801	England	Thomas Young uses diffraction and interference patterns to demonstrate that light has wavelike characteristics.
1801	Germany	Johann Ritter discovers ultraviolet light.
1808	France	Etienne Malus discovers the polarization of light.
1815	France	Jean Biot discovers that the plane of polarized light is twisted in different directions by different organic liquids.
1818	France	Augustin Fresnel’s Memoire stir la Diffraction de la Ltuniere demonstrates the ability of a transverse wave theory of light to account for a variety of optical phenomena, converting many scientists to a wave theory.
1820	Denmark	Hans Orsted invents the ammeter.
1820	Denmark	Hans Orsted demonstrates that electricity and magnetism are related, jointly (with Ampere) founding the science of electrodynamics.
1820	Germany	Johann Schweigger invents the needle galvanometer, later essential for the telegraph.
1821	England	Michael Faraday’s “On Some New Electromagnetic Motions” reports his discovery that electrical forces can produce motion and describes the principle of the electric motor.
1822	France	Jean Fourier’s Theorie Analytique de la C/zu/cw applies Fourier’s theorem to the study of heat flow, an influential application of mathematics to physical phenomena.
1822	Germany	Thomas Seebeck discovers that two different metals will generate electricity if their points of juncture are maintained at different temperatures, the Seebeck effect, and demonstrates thermoelectricity.
1823	England	William Sturgeon invents the electromagnet.
1824	France	Nicolas Carnot’s Reflexions stir la Puissance Motrice du Feu is the first scientific analysis of steam engine efficiency, founding thermodynamics.
1827	France	Andre Ampere publishes Ampere’s Law, a mathematical expression of Orsted’s relationship between magnetism and electricity.
1827	Germany	Georg Ohm publishes Ohms Law, that an electrical current is equal to the ratio of the voltage to the resistance, a founding event in electrical engineering.
1827	Scotland	Robert Brown discovers continuous random movement of microscopic solid particles when suspended in a fluid, later known as Brownian motion.
1829	Scotland	William Nicol invents the Nicol prism for measuring the degree of twist in a plane of polarized lead, founding polarimetry.
1829	USA	Joseph Henry uses insulated wire to create an electromagnet able to lift a ton of iron.
1831	England, USA	Michael Faraday and Joseph Henry independently discover that a changing magnetic force can generate electricity, the phenomenon of electromagnetic induction.
1832	England	Michael Faraday discovers the basic laws of electrolysis that govern the production of a chemical reaction by passing electric current through a liquid or solution.
1834	France	Jean Peltier discovers the Peltier effect, that a current flowing across a junction of two dissimilar metals causes heat to be absorbed or freed, depending on the direction in which the current is flowing.
1839	France	Alexandre Becquerel discovers the photovoltaic effect, whereby light can be used to induce chemical reactions that produce an electric current.
1842	Germany	Christian Doppler discovers the Doppler effect, that the frequency of waves emitted by a moving source changes when the source moves relative to the observer.
1842	Germany	Julius von Mayer and Carl Mohr develop early formulations of the concept of conservation of energy.
1843	England	James Joule discovers Joules first law, describing the heat produced when an electric current flows through resistance for a given time.
1847	Germany	Hermann von Helmholtz states the law of conservation of energy, the first law of thermodynamics: in an isolated system, the total amount of energy does not change.
1848	Scotland	William Thomson (Baron Kelvin) defines absolute zero and proposes the Kelvin scale.
1849	France	Armand-Hippolyte-Louis Fizeau and Jean-Bernard-Leon Foucault determine the speed of light to within less than one percent error.
1850	England	George Stokes discovers the terminal velocity of objects falling through viscous liquid.
1850	Germany	Rudolf Clausius discovers the second law of thermodynamics, that the disorder of a closed system increases with time.
1851	France	Jean-Bernard-Leon Foucault demonstrates the rotation of the earth with the Foucault pendulum.
1852	England	James Joule and William Thomson discover the Joule-Thomson effect, which later permits liquefaction of some permanent gases.
1855	Germany, England	Johann Geissler invents Geissler tubes, producing a better vacuum. As improved by William Crookes, the tubes produce cathode rays, leading to discovery of the electron.
1865	Scotland	James Maxwell’s “A Dynamical Theory of the Electromagnetic Field” presents Maxwell’s equations describing the behavior of electric and magnetic fields and proposes that light is electromagnetic in character, constituting the first theoretical unification of physical phenomena.
1873	Scotland	James Maxwell’s A Treatise on Electricity and Magnetism elaborates the mathematical model of electromagnetic waves, predicting such phenomena as radio waves and pressure caused by light rays.
1875	England	William Crookes invents the radiometer, thereby providing support for the kinetic theory of gases.
1876	Germany	Eugen Goldstein discovers cathode rays, streams of fluorescence flowing from the negatively charged electrode in an evacuated tube.
1876	USA	Josiah Gibbs publishes the first of a series of papers applying thermodynamics to chemical change, defining the concepts of free energy, chemical potential, equilibrium between phases of matter, and the phase rule, thereby establishing general principles of physical chemistry.
1879	Austria	Josef Stefan discovers Stefan s Law, that the radiation of a body is proportional to the fourth power of its absolute temperature.
1879	USA	Edwin Hall discovers the Hall effect, enabling a method of measuring the strength of strong magnetic fields in small spaces.
1880	France	Pierre and Jacques Curie discover that ultrasonic vibrations are produced by piezoelectricity.
1883	USA	Thomas Edison discovers the Edison effect, later a major factor in the invention of the vacuum tube.
1886	Germany	Heinrich Hertz produces radio waves in the laboratory, confirming Maxwell’s electromagnetic theory and laying the basis for radio, television, and radar.
1887	USA	Albert Michelson and Edward Morley fail to confirm the existence of ether and demonstrate that the speed of light is a constant, raising questions about the adequacy of classical physics.
1888	Germany	Eugen Goldstein discovers canal rays, from cathode rays.
1892	Ireland	George Fitzgerald hypothesizes the Fitzgerald contraction, that distance contracts with speed, accounting for the results of the Michelson-Morley experiment.
1892	Russia	Konstantin Tsiolkovsky begins theoretical work on rocket propulsion and space flight.
1892	Scotland	James Dewar invents the Dewar flask.
1895	Germany	Wilhelm Rontgen discovers X-rays.
1895	Netherlands	Hendrik Antoon Lorentz extends Fitzgerald's work, hypothesizing that mass also increases with velocity, leading to the conclusion that the speed of light is a universal maximum.
1895	Scotland	Charles Wilson invents the cloud chamber, which later becomes an indispensable tool in the study of atomic particles.
1896	France	Antoine Becquerel discovers spontaneous radioactivity.
1896	Netherlands	Pieter Zeeman discovers the splitting of lines in a spectrum when the spectrum’s source is exposed to a magnetic field, the Zeeman effect, later used to study the fine details of atomic structure.
1897	England	J.J. Thomson discovers the first subatomic particle, the electron.
1897	France	Marie and Pierre Curie demonstrate that uranium radiation is an atomic phenomenon, not a molecular phenomenon, and coin the word radioactivity.
1899	England	Ernest Rutherford discovers two types of uranium radiation, alpha rays (massive and positively charged) and beta rays (lighter and negatively charged).
1900	France	Antoine-Henri Becquerel demonstrates that the process of radioactivity consists partly of particles identical to the electron.
1900	Germany	Max Planck discovers Planck’s Law of black body radiation, introducing Planck’s constant and the concept that energy is radiated in discrete packets called quanta, founding quantum physics.
1902	England	Ernest Rutherford and Frederick Soddy demonstrate that uranium and thorium break down into a series of radioactive intermediate elements.
1904	England	J. J. Thomson proposes the “plum-pudding” model of the atom in which electrons are embedded in a sphere of positive electricity.
1905	Switzerland	Albert Einstein’s “Zur Elektrodynamik bewegter Korpen” introduces the special theory of relativity.
1905	Switzerland	Albert Einstein shows that the assumption that light is quantized can explain the photoelectric effect.
1905	Switzerland	Albert Einstein deduces as a consequence of the special theory of relativity that the mass of a body is a measure of its energy content, expressed as E=mc2.
1905	Switzerland	Albert Einstein explains Brownian motion mathematically, the most convincing evidence to date for the existence of molecules and atoms, and proposes a method to deduce the size of molecules and atoms.
1906	Germany	Hermann Nernst states the third law of thermodynamics, that all bodies at absolute zero would have the same entropy, though absolute zero cannot be perfecdy attained.
1908	England	Ernest Rutherford and Johannes Geiger invent an alpha-particle counter.
1908	France	Jean Perrin calculates atomic size from Brownian motion.
1911	England	Ernest Rutherford, using experimental results from Ernst Marsden and Johannes Geiger, proposes the concept of the atomic nucleus, leading to the deduction of the true nature of the atom.
1911	Netherlands	Heike Kamerlingh-Onnes discovers superconductivity, the disappearance of electrical resistance in certain substances as they approach absolute zero.
1911	USA	Victor Hess discovers the phenomenon later called cosmic rays.
1912	Germany	Max von Laue develops X-ray diffraction using crystals, founding X-ray crystallography.
1913	Denmark	Niels Bohr applies quantum theory to the structure of the atom, describing electron orbits and electron excitation and de­-excitation.
1913	England	Frederick Soddy and Kasimir Fajans discover isotopes, leading to the radioactive displacement law.
1913	USA	Robert Millikan completes experiments determining the charge of an electron, leading to the conclusion that the electron is the fundamental unit of electricity.
1914	England	Henry Moseley introduces the concept of atomic number, the amount of positive charge on the nucleus, for classifying atoms.
1914	England	Ernest Rutherford discovers the proton.
1916	Germany	Albert Einstein’s general theory of relativity describes space as a curved field modified locally by the existence of mass, replacing Newtonian ideas which invoke a force of gravity, and derives the basic equations for the exchange of energy between matter and radiation.
1919	England	Francis Aston invents the mass spectrograph to measure the mass of atoms.
1919	England	Francis Aston discovers isotopes in non-radioactive elements and states the whole-number rule.
1919	England	Ernest Rutherford uses atomic bombardment to alter atomic nuclei, transforming one element into another and constituting the first nuclear reaction.
1923	France	Louis de Broglie states that every particle should have an associated matter wave whose wavelength is inversely related to the particles momentum, providing an explanation for the wave-particle duality of light.
1923	USA	Arthur Compton discovers the Compton effect, whereby the wavelength of X-rays and gamma rays increases following collisions with electrons.
1925	Germany	Wolfgang Pauli develops the exclusion principle, stating that in a given atom no two electrons can have the identical set of four quantum numbers.
1926	Austria	Erwin Schrodinger develops the mathematics of wave mechanics, including the Schrodinger wave equation.
1927	England	Paul Dirac’s relativistically invariant form of the wave equation of the electron unifies aspects of quantum mechanics and relativity theory.
1927	Germany	Werner Heisenbergs “On the Intuitive Content of Quantum Kinematics and Mechanics” introduces the uncertainty principle.
1928	Denmark	Niels Bohr’s “The Philosophical Foundations of Quantum Theory” introduces the principle of complementarity, arguing that different but complementary models may be needed to explain the full range of atomic and subatomic phenomena.
1930	England	Paul Dirac predicts the existence of antimatter.
1930	USA	Nils Edlefsen and Ernest Lawrence invent the cyclotron, an instrument used to produce directed beams of charged particles that transforms research into fine nuclear structure.
1931	Switzerland	Wolfgang Pauli predicts the existence of the particle later named the neutrino.
1932	England	James Chadwick discovers the neutron.
1932	England	John Cockroft achieves a nuclear reaction by splitting the atomic nucleus.
1932	USA	Robert Millikan and Carl Anderson discover the positron, the first antiparticle.
1933	Germany	Ernst Ruska and Reinhold Ruedenberg invent an electron microscope that is more powerful than a conventional light microscope.
1934	Russia	Pavel Cherenkov, Ilya Frank, and Igor Tamm discover and interpret the Cherenkov effect, the wave of light produced by particles apparently moving faster than the speed of light in a medium other than a vacuum.
1934	USA	Enrico Fermi achieves the first nuclear fission reaction.
1935	Japan	Hideki Yukawa predicts the existence of mesons as fundamental carriers of the nuclear force field.
1938	Germany	Otto Hahn and Friedrich Strassman split an atomic nucleus into two parts by bombarding uranium-235 with neutrons.
1940	USA	Martin Kamen discovers carbon-14, the most useful of all the radioactive tracers.
1942	USA	Enrico Fermi, Walter Zinn, and Herbert Anderson achieve the first sustained nuclear reaction.
1943	USA, Japan	Richard Feynman, Julian Schwinger, and Sin-Itiro Tomonaga independently work out the equations of quantum electrodynamics governing the behavior of electrons and electromagnetic reactions generally.
1945	Russia, USA	Edwin McMillan and Vladimir Veksler independently invent the synchrotron.
1947	England	Dennis Gabor develops the basic concept of holography, which must wait on the laser for implementation.
1948	USA	John Bardeen, Walter Brattain, and William Shockley discover the transistor effect.