Janez Strnad
Encyclopedia
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...
and populariser of natural science
Natural science
The natural sciences are branches of science that seek to elucidate the rules that govern the natural world by using empirical and scientific methods...
.
Life and work
Strnad was born in LjubljanaLjubljana
Ljubljana is the capital of Slovenia and its largest city. It is the centre of the City Municipality of Ljubljana. It is located in the centre of the country in the Ljubljana Basin, and is a mid-sized city of some 270,000 inhabitants...
, Kingdom of Yugoslavia
Kingdom of Yugoslavia
The Kingdom of Yugoslavia was a state stretching from the Western Balkans to Central Europe which existed during the often-tumultuous interwar era of 1918–1941...
(now Slovenia
Slovenia
Slovenia , officially the Republic of Slovenia , is a country in Central and Southeastern Europe touching the Alps and bordering the Mediterranean. Slovenia borders Italy to the west, Croatia to the south and east, Hungary to the northeast, and Austria to the north, and also has a small portion of...
).
He taught for many years from 1961 at the University of Ljubljana
University of Ljubljana
The University of Ljubljana is the oldest and largest university in Slovenia. With 64,000 enrolled graduate and postgraduate students, it is among the largest universities in Europe.-Beginnings:...
, Faculty for natural science and technology
Technology
Technology is the making, usage, and knowledge of tools, machines, techniques, crafts, systems or methods of organization in order to solve a problem or perform a specific function. It can also refer to the collection of such tools, machinery, and procedures. The word technology comes ;...
on the Department of physics introductory courses and topics from physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
. His surname Strnad in English
English language
English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...
means a yellowhammer
Yellowhammer
The Yellowhammer, Emberiza citrinella, is a passerine bird in the bunting family Emberizidae. It is common in all sorts of open areas with some scrub or trees and form small flocks in winter....
, it also is a type of bird, like a swallow.
He took a degree at the University of Ljubljana in technical physics in 1957, and got his Ph.D.
Doctor of Philosophy
Doctor of Philosophy, abbreviated as Ph.D., PhD, D.Phil., or DPhil , in English-speaking countries, is a postgraduate academic degree awarded by universities...
in 1963. His main research work was carried out at the Jožef Stefan Institute. In 1974 he became a full professor. In 1990 he wrote his beautiful and famous book about fundamental particles physics entitled Iz take so snovi kot sanje (We are such stuff as dream
Dream
Dreams are successions of images, ideas, emotions, and sensations that occur involuntarily in the mind during certain stages of sleep. The content and purpose of dreams are not definitively understood, though they have been a topic of scientific speculation, philosophical intrigue and religious...
s are made of). With his short and long articles he had deepened the knowledge about Stefan
Joseph Stefan
Joseph Stefan was a physicist, mathematician, and poet of Slovene mother tongue and Austrian citizenship.- Life and work :...
's scientific
Science
Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe...
work. His thick booklet in the series of monographs, Zbirka Sigma (the Sigma Collection), entitled Kvantna fizika (Quantum Physics), (DZS, Ljubljana 1974) contains an almost 'perfect' definition and introduction to the understanding of Heisenberg
Werner Heisenberg
Werner Karl Heisenberg was a German theoretical physicist who made foundational contributions to quantum mechanics and is best known for asserting the uncertainty principle of quantum theory...
's uncertainty principle
Uncertainty principle
In quantum mechanics, the Heisenberg uncertainty principle states a fundamental limit on the accuracy with which certain pairs of physical properties of a particle, such as position and momentum, can be simultaneously known...
for the graduate beginner. He wrote over 1000 works.
Anyone who knows him can describe his piercing nature and precise ways of expression through his own simple words of what Lev Davidovich Landau once meant:
- "We can find similar thoughts by the other cosmologists,
- which have reputation they are wrong many times, but they never doubt"
-
- Janez Strnad from a review on Mirjam Galičič's translation of
- Stephen HawkingStephen HawkingStephen William Hawking, CH, CBE, FRS, FRSA is an English theoretical physicist and cosmologist, whose scientific books and public appearances have made him an academic celebrity...
's A Brief History of TimeA Brief History of TimeA Brief History of Time is a popular science book written by renown physicist Stephen Hawking and first published by the Bantam Dell Publishing Group in 1988. It became a best-seller and has sold more than 10 million copies...
(Obzornik mat, fiz. 39 (1994) 6, pp 191 - 192).
Strnad's works also includes topics of physics which are not exactly related at first glance to it, for instance as in this his article Znanost in politika v vinjetah (Science and politics in vignettes) available on the net.
- "Richarda Feynmana je vznejevoljil prijatelj astronom, ki se je hvalil z uporabnostjo svojih
- raziskovanj o vesolju. Po njegovem mnenju to ni bilo pošteno. Raziskovalec naj pojasni laikom,
- kaj dela, in "če ga v takih okoliščinah nočejo podpirati, je to njihova stvar"..
University textbooks
- Janez Strnad, Atlas klasične in moderne fizike (Atlas of classical and modern physics), translation and adaptation of Hans Breuer, dtv-Atlas zur Physik, (Deutscher Taschenbuch Verlag, München 1987, 1988), DZS, Ljubljana 1993, pp 400, .
- Janez Strnad, Fizika, 1. del, Mehanika, Toplota (Physics, 1st part, MechanicsMechanicsMechanics is the branch of physics concerned with the behavior of physical bodies when subjected to forces or displacements, and the subsequent effects of the bodies on their environment....
, HeatHeatIn physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
), (DZS, Ljubljana 1977, pp 1 – 284. - Janez Strnad, Fizika, 2. del, Elektrika, Optika (Physics, 2nd part, ElectricityElectricityElectricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...
, OpticsOpticsOptics is the branch of physics which involves the behavior and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behavior of visible, ultraviolet, and infrared light...
), (DZS, Ljubljana 1978, pp 285 – 564). - Janez Strnad, Fizika, 3. del, Posebna teorija relativnosti, Atomi (Physics, 3rd part, Special Theory of relativitySpecial relativitySpecial relativity is the physical theory of measurement in an inertial frame of reference proposed in 1905 by Albert Einstein in the paper "On the Electrodynamics of Moving Bodies".It generalizes Galileo's...
, AtomAtomThe atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...
s), (DZS, Ljubljana 1980, pp 320). - Janez Strnad, Fizika, 4. del, Molekule, kristali, jedra, delci (Physics, 4th part, MoleculeMoleculeA molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...
s, CrystalCrystalA crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. The scientific study of crystals and crystal formation is known as crystallography...
s, NucleiAtomic nucleusThe nucleus is the very dense region consisting of protons and neutrons at the center of an atom. It was discovered in 1911, as a result of Ernest Rutherford's interpretation of the famous 1909 Rutherford experiment performed by Hans Geiger and Ernest Marsden, under the direction of Rutherford. The...
, Particles), (DZS, Ljubljana 1982, pp 283). - Janez Strnad, Mladen Gros, Marjan Hribar, Alojz Kodre, Naloge iz fizike (Exercises from Physics), (DMFA SRS, Ljubljana 1981, pp 108).
Selected chapters from physics and postgraduate seminars
- Janez Strnad, Fazna, skupinska, signalna hitrost (Phase, Group, Signal VelocityVelocityIn physics, velocity is speed in a given direction. Speed describes only how fast an object is moving, whereas velocity gives both the speed and direction of the object's motion. To have a constant velocity, an object must have a constant speed and motion in a constant direction. Constant ...
), (DMFA SRS, Ljubljana 1975, pp 31). - Janez Strnad, Poskusi v posebni in splošni teoriji relativnosti (Experiments in Special and General Theory of RelativityGeneral relativityGeneral relativity or the general theory of relativity is the geometric theory of gravitation published by Albert Einstein in 1916. It is the current description of gravitation in modern physics...
), (DMFA SRS, Ljubljana 1977, pp 44). - Janez Strnad, Na pot v kvantno elektrodinamiko (On the way to the Quantum ElectrodynamicsQuantum electrodynamicsQuantum electrodynamics is the relativistic quantum field theory of electrodynamics. In essence, it describes how light and matter interact and is the first theory where full agreement between quantum mechanics and special relativity is achieved...
), (DMFA SRS, Ljubljana 1986, pp 176). - Janez Strnad, Na pot k Schwarzschildu (On the way to SchwarzschildKarl SchwarzschildKarl Schwarzschild was a German physicist. He is also the father of astrophysicist Martin Schwarzschild.He is best known for providing the first exact solution to the Einstein field equations of general relativity, for the limited case of a single spherical non-rotating mass, which he accomplished...
), (DMFA S, Ljubljana 1991, pp 52). - Janez Strnad, Homogeno gravitacijsko polje: med posebno in splošno teorijo relativnosti (Homogeneous Gravitational Field: Between Special and General Theory of relativity), (DMFA S, Ljubljana 1994, pp 44).
- Janez Strnad, Začetki kvantne statistične mehanike (The Beginnings of Quantum Statistical MechanicsStatistical mechanicsStatistical mechanics or statistical thermodynamicsThe terms statistical mechanics and statistical thermodynamics are used interchangeably...
), (DMFA S, Ljubljana 1997, pp 31). - Janez Strnad, Odkritje razcepa (Discovery of the split), (DMFA S, Ljubljana 2000, pp 39).
Books
- Janez Strnad, Jožef Stefan, Ob stopetdesetletnici rojstva (Jožef Stefan, By his 150th anniversary of birth), (DMFA SRS, Ljubljana 1985).
- Janez Strnad, Prapok Prasnov požene v dir (Primordial BangBig BangThe Big Bang theory is the prevailing cosmological model that explains the early development of the Universe. According to the Big Bang theory, the Universe was once in an extremely hot and dense state which expanded rapidly. This rapid expansion caused the young Universe to cool and resulted in...
drives Primordial Substance into a Gallop), (DZS, Ljubljana 1988, pp 81). - Janez Strnad, Zgodbe iz fizike (Stories from Physics), (Slovenska matica, Ljubljana 1990).
- Janez Strnad, Fiziki 1 (Physicists 1), (Mihelač in Nešović, Ljubljana 1995, pp 159).
- Janez Strnad, Razvoj fizike (The Development of Physics), (DZS Ljubljana 1996, pp 400).
- Janez Strnad, Fiziki 2 (Physicists 2), (Modrijan, Ljubljana 1999, pp 199).
- Janez Strnad, Fiziki 3 (Physicists 3), (Modrijan, Ljubljana 2000, pp 227).
- Janez Strnad, Svet merjenj: o razvoju fizike in merjenju osnovnih fizikalnih količin (The World of Measurements: About the Development of Physics and Measuring of Fundamental Physical QuantitiesPhysical quantityA physical quantity is a physical property of a phenomenon, body, or substance, that can be quantified by measurement.-Definition of a physical quantity:Formally, the International Vocabulary of Metrology, 3rd edition defines quantity as:...
), (DZS, Ljubljana 2001, pp 139). - Janez Strnad, Sto let fizike: od 1900 do 2000 (A Hundred Years of Physics: from 1900 to 2000), (DMFA S, Ljubljana 2001, pp 233).
Scientific Articles
- Janez Strnad, Sto let Stefanovega zakona (Hundred years of Stefan's law), (Obzornik mat, fiz. 26 (1979) 3).
- Janez Strnad, A. Vengar, Stefanova meritev toplotne prevodnosti zraka (Stefan's measurements of the thermal conductivityThermal conductivityIn physics, thermal conductivity, k, is the property of a material's ability to conduct heat. It appears primarily in Fourier's Law for heat conduction....
of airEarth's atmosphereThe atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention , and reducing temperature extremes between day and night...
), (European Journal of Physics, 1984). - Janez Strnad, Kako je Jožef Stefan odkril zakon o sevanju (How Jožef Stefan discovered the law of radiationRadiationIn physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...
), (Zbornik za zgodovino naravoslovja in tehnike 8, Ljubljana 1985). - Janez Strnad, Stefanov tok (Stefan's current), (Obzornik mat, fiz. 32 (1985).
- Janez Strnad, Stefanova naloga (Stefan's task), (Obzornik mat, fiz. 34 (1987).
- Janez Strnad, Stefanove elektodinamične enačbe (Stefan's equations of electrodynamics), (European Journal of Physics, 1989).
- Janez Strnad, Ernst Mach kot fizik (Ernst Mach as physicist), (Zbornik za zgodovino naravoslovja in tehnike 10, Ljubljana 1989).
- Janez Strnad, Dvigajoči se mehurčki (Rising bubbles), (Obzornik mat, fiz. 39 (1992) 4, pp 85 – 89).
- Janez Strnad, Oslabitev Brownovega gibanja (Squeezing Brownian motionBrownian motionBrownian motion or pedesis is the presumably random drifting of particles suspended in a fluid or the mathematical model used to describe such random movements, which is often called a particle theory.The mathematical model of Brownian motion has several real-world applications...
), (Obzornik mat, fiz. 39 (1992) 2, pp 49 – 54). - Janez Strnad, Opazovanje in teorija (ObservationObservationObservation is either an activity of a living being, such as a human, consisting of receiving knowledge of the outside world through the senses, or the recording of data using scientific instruments. The term may also refer to any data collected during this activity...
and theoryTheoryThe English word theory was derived from a technical term in Ancient Greek philosophy. The word theoria, , meant "a looking at, viewing, beholding", and referring to contemplation or speculation, as opposed to action...
), (Obzornik mat, fiz. 39 (1992) 5, pp 141 – 150). - Janez Strnad, J. Stefana 'Longitudinalna nihanja palic' (J. Stefan's 'Longitudal oscillationOscillationOscillation is the repetitive variation, typically in time, of some measure about a central value or between two or more different states. Familiar examples include a swinging pendulum and AC power. The term vibration is sometimes used more narrowly to mean a mechanical oscillation but sometimes...
s of rods' ), (Obzornik mat, fiz. 40 (1993) 1, pp 17 – 19). - Janez Strnad, Ali mora znati, kdor uči? (Should he who teaches know?), (Obzornik mat, fiz. 40 (1993) 1, pp 23 – 31).
- Janez Strnad, Superprevodnost (SuperconductivitySuperconductivitySuperconductivity is a phenomenon of exactly zero electrical resistance occurring in certain materials below a characteristic temperature. It was discovered by Heike Kamerlingh Onnes on April 8, 1911 in Leiden. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum...
), (Obzornik mat, fiz. 40 (1993) 4, pp 110 – 120). - Janez Strnad, Nenavadni interferenčni poskusi I. Interferenčni poskus s sevanjema v nasprotnih smereh (Unusual interference experiments I. Interference experiment with radiations in opposite directions), (Obzornik mat, fiz. 40 (1993) 5, pp 135 – 136).
- Janez Strnad, Supertekočnost (Superfluidity), (Obzornik mat, fiz. 40 (1993) 6, pp 183 – 191).
- Janez Strnad, Fizika iz Karlsruheja: O novostih v poučevanju fizike (The KarlsruheKarlsruheThe City of Karlsruhe is a city in the southwest of Germany, in the state of Baden-Württemberg, located near the French-German border.Karlsruhe was founded in 1715 as Karlsruhe Palace, when Germany was a series of principalities and city states...
physics course: On new approaches in physics teaching), (Obzornik mat, fiz. 41 (1994) 4, pp 122 – 128). - Janez Strnad, Nenavadni interferenčni poskusi I. Youngov poskus z ionoma (Unusual interference experiments I. Young's experiment with two ionIonAn ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...
s), (Obzornik mat, fiz. 41 (1994) 5, pp 119 – 153). - Janez Strnad, Nenavadni interferenčni poskusi, Interferenčni poskus z laserjema (Unusual interference experiments, Interference experiment with two laserLaserA laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...
s), (Obzornik mat, fiz. 41 (1994) 6, pp 187 – 190) (PACS 42.50.-p.) - Janez Strnad, Premo centralno gibanje J. Vege (J. VegaJurij VegaBaron Jurij Bartolomej Vega was a Slovene mathematician, physicist and artillery officer.-Early life:...
's linear central motionMotion (physics)In physics, motion is a change in position of an object with respect to time. Change in action is the result of an unbalanced force. Motion is typically described in terms of velocity, acceleration, displacement and time . An object's velocity cannot change unless it is acted upon by a force, as...
), (Obzornik mat, fiz. 47 (2000) 1, pp 20 – 26). (PACS 01.65.+g, 45.40GJ) - Janez Strnad, Nenavadni interferenčni poskusi, Interferenčni poskus z molekulami C60 (Unusual interference experiments, An interference experiment with C60 molecules), (Obzornik mat, fiz. 47 (2000) 2, pp 53 – 56) (PACS 33.80.-b.)
- Janez Strnad, Precesija enakonočij (The precessionPrecessionPrecession is a change in the orientation of the rotation axis of a rotating body. It can be defined as a change in direction of the rotation axis in which the second Euler angle is constant...
of equinoxes), (Obzornik mat, fiz. 47 (2000) 4, pp 120 – 125). (PACS 01.65.+g) - Janez Strnad, Osnovne fizikalne konstante 1998 (Fundamental physical constants 1998), (Obzornik mat, fiz. 47 (2000) 5, pp 177 – 179). (PACS 06.20.Jr)
- Janez Strnad, Rubinowicz v Ljubljani (Rubinowics in Ljubljana), (Obzornik mat, fiz. 47 (2000) 6, pp 144 – 146). (PACS 01.60.+g)
- Janez Strnad, O gravitacijski konstanti (On the Newtonian gravitational constantGravitational constantThe gravitational constant, denoted G, is an empirical physical constant involved in the calculation of the gravitational attraction between objects with mass. It appears in Newton's law of universal gravitation and in Einstein's theory of general relativity. It is also known as the universal...
), (Obzornik mat, fiz. 48 (2001) 1, pp 19 – 25). (PACS 04.80.-y) - Janez Strnad, Med dvema ognjema? (Between two fires?), (Obzornik mat, fiz. 48 (2001) 1, pp 92 – 94). (PACS 06.20.Fn)
- Janez Strnad, Sevalni tlak in P. N. Lebedev (Radiation Pressure and P. N. Lebedev), (Obzornik mat, fiz. 48 (2001) 1, pp 148 – 153). (PACS 01.65.+g, 45.40GJ)
- Janez Strnad, Prožni trak kot model vesolja (The elastic ribbon as a model universe), (Obzornik mat, fiz. 49 (2002) 1, pp 21 – 27). (PACS 98.80.-k)
- Janez Strnad, Stefanova sila (Stefan's force), (Obzornik mat, fiz. 49 (2002) 2, pp 58 – 61). (PACS 01.65.+g, 47.15.-x)
- Janez Strnad, Interferenca elektronov na svetlobi (Interference of electronElectronThe electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...
s on lightLightLight or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...
), (Obzornik mat, fiz. 49 (2002) 5, pp 148 – 150). (PACS 33.80.-b) - Janez Strnad, Vega o obliki Zemlje (Vega on the form of the EarthEarthEarth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
), (Obzornik mat, fiz. 50 (2003) 1, pp 27 - III). (PACS 01.65.+g, 45.40GJ) - Janez Strnad, O elektronih v atomu (On electrons in atom), (Obzornik mat, fiz. 50 (2003) 3, pp 82 – 85). (PACS 01.40.Ej)
- Janez Strnad, Kako sem pisal učbenik za fiziko (How I wrote a physics textbook), (Obzornik mat, fiz. 50 (2003) 5, pp 157 – 160). (PACS 01.40.Gm)
- Janez Strnad, Bose-Einsteinova kondenzacija cezija (Bose-Einstein condensation of cesium), (Obzornik mat, fiz. 50 (2003) 6, pp 184 – 191). (PACS 03.75.Fi)
Popular Arcticles
- Janez Strnad, Jožef Stefan, Ob stopetdesetletnici rojstva (Jožef Stefan, By his 150th anniversary of birth), (Presek (1985) 5).
- Janez Strnad, Stogodišnjica Stefanovega zakona (Hundred years of Stefan's law), (Dijalektika, BelgradeBelgradeBelgrade is the capital and largest city of Serbia. It is located at the confluence of the Sava and Danube rivers, where the Pannonian Plain meets the Balkans. According to official results of Census 2011, the city has a population of 1,639,121. It is one of the 15 largest cities in Europe...
1979 3-4). - Janez Strnad, Svetlobni mlinček (Light grinder), (Presek 24 (1996/1997) 130).
- Janez Strnad, Natančnejši podatki o vesolju (More accurate data about the Universe), (Delo, Znanost/Scientia, April 7, 2003 pp 3)
Colloquiums
- Janez Strnad, Bose-Einsteinova kondenzacija alkalijskih atomov (Bose-Einstein's condensation of alkaline atoms), (FMF, IJS, Ljubljana November 5, 2001).
- Janez Strnad, Nobelova nagrada za fiziko 2000 (Nobel prize for physicsNobel Prize in PhysicsThe Nobel Prize in Physics is awarded once a year by the Royal Swedish Academy of Sciences. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895 and awarded since 1901; the others are the Nobel Prize in Chemistry, Nobel Prize in Literature, Nobel Peace Prize, and...
2000), (FMF, IJS, Ljubljana November 6, 2000). - Janez Strnad, Alojz Kodre, Profesor Kuščer - In Memoriam (In memory of professor Kuščer), (FMF, IJS, Ljubljana February 2, 2000).