Jožef Stefan
Jožef Stefan in one of his very rare photographs
Born
March 24, 1825 St. Peter near Klagenfurt, Austria
Died
January 7, 1893 Vienna, Austria

Joseph Stefan (Slovene Jožef Stefan) (March 24, 1835 – January 7, 1893) was a Slovene physicist, mathematician and poet. 19th century photograph. ... March 24 is the 83rd day of the year in the Gregorian Calendar (84th in Leap years). ... 1825 was a common year starting on Saturday (see link for calendar). ... Lindwurm Brunnen in the center of Klagenfurt Klagenfurt (Slovenian Celovec) is the capital of the federal state of Carinthia (German Kärnten; Slovenian Koróška), in Austria, on the Glan river. ... January 7 is the seventh day of the year in the Gregorian calendar. ... 1893 (MDCCCXCIII) was a common year starting on Sunday (see link for calendar). ... Vienna (German: Wien ; Bosnian, Croatian, and Serbian: Beč, Czech: Vídeň, Hungarian: Bécs, Romanian: Viena, Romani: Bech or Vidnya, Russian: Вена, Slovak: Viedeň, Slovenian: Dunaj) is the capital of Austria, and also one of the nine States of Austria. ... March 24 is the 83rd day of the year in the Gregorian Calendar (84th in Leap years). ... | Come and take it, slogan of the Texas Revolution 1835 was a common year starting on Thursday (see link for calendar). ... January 7 is the seventh day of the year in the Gregorian calendar. ... 1893 (MDCCCXCIII) was a common year starting on Sunday (see link for calendar). ... A physicist is a scientist trained in physics. ... Leonhard Euler is considered by many people to be one of the greatest mathematicians of all time A mathematician is a person whose primary area of study and research is mathematics. ... A poet is some one who writes poetry. ...

Nekaj bode zmeraj še ostalo,	There always something will remain,
da ne bomo vedeli, zakaj?	that we shall not know, why?
	Jožef Stefan, Naturoznanske poskušnje (The Science of Nature trials), 1859

Stefan was born in an outskirt village St. Peter (Slovene Sveti Peter) near Klagenfurt (Slovene Celovec) in Austria-Hungary (now in Austria) to father Aleš (Aleksander) Stefan, born in 1805 and mother Marija Startinik, born 1815. His parents, both ethnic Slovenes, were married when Jožef was eleven. The Stefans were a modest family. His father was a milling assistant and mother served as a maidservant. Stefan's father died in 1872 while his mother died almost ten years earlier in 1863. 1859 (MDCCCLIX) is a common year starting on Saturday of the Gregorian calendar (or a common year starting on Monday of the Julian calendar). ... Lindwurm Brunnen in the center of Klagenfurt Klagenfurt (Slovenian Celovec) is the capital of the federal state of Carinthia (German Kärnten; Slovenian Koróška), in Austria, on the Glan river. ... Austria-Hungary, also known as the Dual monarchy (or: the k. ... 1805 was a common year starting on Tuesday (see link for calendar). ... The Battle of New Orleans 1815 was a common year starting on Sunday (see link for calendar). ... 1872 (MDCCCLXXII) was a leap year starting on Monday (see link for calendar) of the Gregorian calendar or a leap year starting on Wednesday of the 12-day-slower Julian calendar. ... 1863 (MDCCCLXIII) is a common year starting on Thursday of the Gregorian calendar (or a common year starting on Saturday of the Julian calendar). ...

Stefan attended elementary school in Klagenfurt, where he showed his talent. They recommended that he continue his schooling, so in 1845 he went to Klagenfurt gymnasium. He experienced the revolutionary year of 1848, as a thirteen-year-old boy, which inspired him to be sympathetic toward Slovene literary production. 1845 was a common year starting on Wednesday (see link for calendar). ... 1848 is a leap year starting on Saturday of the Gregorian calendar. ... Slovene literature starts with Freising manuscripts around 1000. ...

When he had finished gymnasium as the best student in his class he thought for a while of joining the Benedictine order but he soon abandoned his idea, because his great interest for physics prevailed. He left for Vienna in 1853 to study mathematics and physics. His professor of physics in gymnasium was Karel Robida who wrote the first Slovene physics textbook. Stefan then graduated in mathematics and physics at the University of Vienna in 1857. During his student years, he also wrote and published a number of poems in Slovene. He taught physics at the University of Vienna, was Director of the Physical Institute from 1866, Vice-President of the Vienna Academy of Sciences and member of several scientific institutions in Europe. A Benedictine is a person who follows the Rule of St Benedict. ... 1853 was a common year starting on Saturday (see link for calendar). ... Euclid, a famous Greek mathematician known as the father of geometry, is shown here in detail from The School of Athens by Raphael. ... Physics (from the Greek, φυσικός (physikos), natural, and φύσις (physis), nature) is the science of the natural world, which deals with the fundamental constituents of the universe, the forces they exert on one another, and the results of these forces. ... University of Vienna, main building, seen from Beethovens apartment The University of Vienna (German: Universität Wien) in Austria was founded in 1365 by Rudolph IV and hence named Alma mater Rudolphina. ... 1857 was a common year starting on Thursday (see link for calendar). ... 1866 (MDCCCLXVI) is a common year starting on Monday of the Gregorian calendar or a common year starting on Wednesday of the 12-day-slower Julian calendar. ... World map showing Europe Europe is one of the seven continents of Earth which, in this case, is more a cultural and political distinction than a physiographic one, leading to various perspectives about Europes borders. ...

He published nearly 80 scientific articles, mostly in the Bulletins of the Vienna Academy of Sciences, and he is best known for originating a physical power law in 1879 stating that the total radiation from a black body j^* is proportional to the fourth power of its thermodynamic temperature T: A physical law, scientific law, or a law of nature is a scientific generalization based on empirical observations of physical behavior. ... See Also: Watt In physics, a power law relationship between two scalar quantities x and y is any such that the relationship can be written as where a (the constant of proportionality) and k (the exponent of the power law) are constants. ... 1879 (MDCCCLXXIX) was a common year starting on Wednesday (see link for calendar). ... Radiation in physics is a process of emission of energy or particles. ... As the temperature decreases, the peak of the black body radiation curve moves to lower intensities and longer wavelengths. ... Thermodynamic temperature is a measure, in kelvins (K) of temperature for thermodynamics, with a uniquely defined zero point at absolute zero. ...

In 1884 the law derived theoretically in the framework of thermodynamics by his student Ludwig Boltzmann and hence known as the Stefan-Boltzmann law. Boltzmann treated a heat engine with light as a working matter. This law is the only physical law of nature named after a Slovene physicist. Today we derive the law from Planck's law of black body radiation: 1884 (MDCCCLXXXIV) is a leap year starting on Tuesday (click on link to calendar) of the Gregorian calendar (or a leap year starting on Thursday of the 12-day-slower Julian calendar). ... Thermodynamics (Greek: thermos = heat and dynamic = change) is the physics of energy, heat, work, entropy and the spontaneity of processes. ... Ludwig Boltzmann Ludwig Eduard Boltzmann (Vienna, Austria-Hungary, February 20, 1844 – Duino near Trieste, September 5, 1906) is an Austrian physicist famous for his founding contributions in the fields of statistical mechanics and statistical thermodynamics. ... Stefan-Boltzmann law (also Stefans law) states that tom is a brain the total energy radiated per unit surface area of a black body in unit time (black-body irradiance), (or the energy flux density (radiant flux) or the emissive power), j* is directly proportional to the fourth power... In engineering and thermodynamics, a heat engine performs the conversion of heat energy to mechanical work by exploiting the temperature gradient between a hot source and a cold sink. Heat is transferred to the sink from the source, and in this process some of the heat is converted into work. ... Prism splitting light Light is electromagnetic radiation with a wavelength that is visible to the eye (visible light) or, in a technical or scientific context, electromagnetic radiation of wavelengths that are studied in the field of optics. ... Black body spectrum as a function of wavelength In physics, the spectral intensity of electromagnetic radiation from a black body at temperature T is given by the Plancks law of black body radiation: where: I(ν) is the amount of energy per unit time per unit surface area per unit...

and is valid only for ideal black objects. With his law Stefan determined the temperature of the Sun's surface and he calculated a value of 5430 °C. This was the first sensible value for the temperature of the Sun. The Sun is the star at the center of Earths solar system. ... A degree Celsius (°C) is a unit of temperature named after the Swedish astronomer Anders Celsius (1701-1744), who first proposed a similar system in 1742. ...

Stefan provided the first measurements of the thermal conductivity of gases, treated evaporation, and among others studied diffusion, heat conduction in fluids. For his treatise on optics he received the Richard Lieben award from the University of Vienna. Based on his calculations of diffusion, modern meteorologists have found a flow between the droplets of water and ice crystals, today named Stefan's flow. In physics, thermal conductivity, k, is the intensive property of a material that indicates its ability to conduct heat. ... A gas is one of the four main phases of matter (after solid and liquid, and followed by plasma), that subsequently appear as a solid material is subjected to increasingly higher temperatures. ... Evaporation is one of the two forms of vaporization. ... Schematic drawing of the effects of diffusion through a semipermeable membrane. ... Heat flow along perfectly insulated wire Heat conduction is the transmission of heat across matter. ... A subset of the phases of matter, fluids include liquids, gases, plasmas and, to some extent, plastic solids. ... Optical redirects here. ... Meteorology is the scientific study of the atmosphere that focuses on weather processes and forecasting. ... Water (from the Old English waeter; c. ... Icicles A natural ice block in Iceland Ice is the solid form of water. ...

Very important are also his electromagnetic equations, defined in vector notation, and works in the kinetic theory of heat. He was among the first physicists in Europe who fully understood Maxwell's electromagnetic theory and one of the few outside of England who expand on it. He calculated inductivity of a coil with a quadratic cross-section, and he corrected Maxwell's miscalculation. He also researched a phenomenon called the skin effect, where high-frequency electric current is greater on the surface of a conductor than in its interior. In physics and in vector calculus, a spatial vector is a concept characterized by a magnitude, which is a scalar, and a direction (which can be defined in a 3-dimensional space by the Euler angles). ... Kinetic theory attempts to explain macroscopic properties of gases, such as pressure, temperature, or volume, by considering their molecular composition and motion. ... In physics, heat is defined as energy in transit. ... James Clerk Maxwell (13 November 1831 – 5 November 1879) was a Scottish mathematical physicist, born in Edinburgh. ... Electromagnetism is the physics of the electromagnetic field: a field, encompassing all of space, which exerts a force on those particles that possess the property of electric charge, and is in turn affected by the presence and motion of such particles. ... Inductance (or electric inductance) is a measure of the amount of magnetic flux produced for a given electric current. ... A coil is a series of loops. ... The skin effect is the tendency of an alternating electric current to distribute itself within a conductor so that the current density near the surface of the conductor is greater than that at its core. ... Electric current is the flow of electric charge. ... In science and engineering, conductors are materials that contain movable charges of electricity. ...

In mathematics the Stefan problems or Stefan's tasks with movable boundary are well known. The problem was first studied by Lamé and Clapeyron in 1831. Stefan solved the problem when he was calculating how quickly a layer of ice on water grows. [[ == YOUR GAY ==]] ... Gabriel Lamé (July 22, 1795, Tours, France - May 1, 1870, Paris, France) was a French mathematician. ... Emile_Clapeyron Benoit Paul Émile Clapeyron (February 26, 1799 - January 28, 1864) was an French engineer and physicist, considered as one of the founders of thermodynamics. ... Leopold I 1831 was a common year starting on Saturday (see link for calendar). ... Frozen Waterfall in the Rhön mountains A natural, 4 tonne, block of ice on a beach in Iceland Ice can refer to any of the 14 known solid phases of water. ...

He died in Vienna, Austria-Hungary. Vienna (German: Wien ; Bosnian, Croatian, and Serbian: Beč, Czech: Vídeň, Hungarian: Bécs, Romanian: Viena, Romani: Bech or Vidnya, Russian: Вена, Slovak: Viedeň, Slovenian: Dunaj) is the capital of Austria, and also one of the nine States of Austria. ...

His life and work is extensively studied by the physicist Janez Strnad. Janez Strnad (born March 4, 1934) is a Slovene physicist and populariser of natural science. ...

See also

• Stefan-Boltzmann constant σ
• Stefan's force

The Stefan-Boltzmann constant (also Stefans constant), denoted with a Greek letter σ, is a derivable physical constant, the constant of proportionality between the total energy radiated per unit surface area of a black body in unit time and the fourth power of the thermodynamic temperature, as per the...

External links

• Jožef Stefan: http://www.ijs.si/stefan.html
• Jožef Stefan Institute, Ljubljana, Slovenia: http://www.ijs.si/
• University of St. Andrews page about Jožef Stefan: http://www-gap.dcs.st-and.ac.uk/~history/Mathematicians/Stefan_Josef.html