Famous Physicists 1800-1950

Christian Doppler 1803-1853
Austrian
experimented with sound waves; derived an expression for the apparent change in wavelength of a wave due to relative motion between the source and observer
Wilhelm E. Weber 1804-1891
German
developed sensitive magnetometers; worked in electrodynamics and the electrical structure of matter
Sir William Hamilton 1805-1865
Irish
developed the principle of least action and the Hamiltonian form of classical mechanics
James Prescott Joule 1818-1889
British
discovered mechanical equivalent of heat
Armand-Hippolyte-Louis Fizeau 1819-1896
French
made the first terrestrial measurement of the speed of light; invented one of the first interferometers; took the first pictures of the Sun on daguerreotypes; argued that the Doppler effect with respect to sound should also apply to any wave motion, particularly that of light
Jean-Bernard-Léon Foucault 1819-1868
French
accurately measured speed of light; invented the gyroscope; demonstrated the Earth’s rotation
Sir George Gabriel Stokes 1819-1903
British
described the motion of viscous fluids by independently discovering the Navier-Stokes equations of fluid mechanics (or hydrodynamics); developed Stokes theorem by which certain surface integrals may be reduced to line integrals; discovered fluorescence
Hermann von Helmholtz 1821-1894
German
developed first law of thermodynamics, a statement of conservation of energy
Rudolf Clausius 1822-1888
German
developed second law of thermodynamics, a statement that the entropy of the Universe always increases
Lord Kelvin
(born William Thomson)
1824-1907
British
proposed absolute temperature scale, of essence to development of thermodynamics
Gustav Kirchhoff 1824-1887
German
developed three laws of spectral analysis and three rules of electric circuit analysis; also contributed to optics
Johann Balmer 1825-1898
Swiss
developed empirical formula to describe hydrogen spectrum
Sir Joseph Wilson Swan 1828-1914
British
developed a carbon-filament incandescent light; patented the carbon process for printing photographs in permanent pigment
James Clerk Maxwell 1831-1879
Scottish
propounded the theory of electromagnetism; developed the kinetic theory of gases
Josef Stefan 1835-1893
Austrian
studied blackbody radiation
Ernst Mach 1838-1916
Austrian
studied conditions that occur when an object moves through a fluid at high speed (the “Mach number” gives the ratio of the speed of the object to the speed of sound in the fluid); proposed “Mach’s principle,” which states that the inertia of an object is due to the interaction between the object and the rest of the universe
Josiah Gibbs 1839-1903
American
developed chemical thermodynamics; introduced concepts of free energy and chemical potential
James Dewar 1842-1923
British
liquified nitrogen and invented the Dewar flask, which is critical for low-temperature work
Osborne Reynolds 1842-1912
British
contributed to the fields of hydraulics and hydrodynamics; developed mathematical framework for turbulence and introduced the “Reynolds number,” which provides a criterion for dynamic similarity and correct modeling in many fluid-flow experiments
Ludwig Boltzmann 1844-1906
Austrian
developed statistical mechanics and applied it to kinetic theory of gases
Roland Eötvös 1848-1919
Hungarian
demonstrated equivalence of gravitational and inertial mass
Oliver Heaviside 1850-1925
English
contributed to the development of electromagnetism; introduced operational calculus and invented the modern notation for vector calculus; predicted existence of the Heaviside layer (a layer of the Earth’s ionosphere)
George Francis FitzGerald 1851-1901
Irish
hypothesized foreshortening of moving bodies (Lorentz-FitzGerald contraction) to explain the result of the Michelson-Morley experiment
John Henry Poynting 1852-1914
British
demonstrated that the energy flow of electromagnetic waves could be calculated by an equation (now called Poynting’s vector)
Henri Poincaré 1854-1912
French
founded qualitative dynamics (the mathematical theory of dynamical systems); created topology; contributed to solution of the three-body problem; first described many properties of deterministic chaos; contributed to the development of special relativity
Janne Rydberg 1854-1919
Swedish
analyzed the spectra of many elements; discovered many line series were described by a formula that depended on a universal constant (the Rydberg constant)
Edwin H. Hall 1855-1938
American
discovered the “Hall effect,” which occurs when charge carriers moving through a material are deflected because of an applied magnetic field – the deflection results in a potential difference across the side of the material that is transverse to both the magnetic field and the current direction
Heinrich Hertz 1857-1894
German
worked on electromagnetic phenomena; discovered radio waves and the photoelectric effect
Nikola Tesla 1857-1943
Serbian-born American
created alternating current