Friedrich Wilhelm Georg Kohlrausch (Rinteln 1840 - Marburg 1910) was a physicist. He was a son of Rudolf Kohlrausch. Weser watershed Rinteln is a small town in Lower Saxony, Germany. ... 1840 is a leap year starting on Wednesday (link will take you to calendar). ... Marburg is a city in Hesse, Germany, on the Lahn river. ... 1910 in topic: Arts Architecture- Art- Film- Literature- Music- Television Science and technology Aviation- Rail transport- Radio- Science Other topics Australia- Canada- Ireland- South Africa- Sport Births- Deaths Lists of leaders: State leaders - Religious leaders 1910 was a common year starting on Saturday (see link for calendar). ... A physicist is a scientist trained in physics. ...

Friedrich Wilhelm Georg Kohlrausch was a German physicist who investigated the electroconductive properties of electrolytes and contributed to the understanding of their behaviour. His research work covered also investigations of elasticity, thermoelasticity, and thermal conduction as well as magnetic and electrical precision measurements. Today, Friedrich Kohlrausch is classed as one of the most important experimental physicists. His early work helped to extend the absolute system of Carl Friedrich Gauß and Wilhelm Weber to include electrical and magnetic measuring units. An electrolyte is a substance which dissociates free ions when dissolved (or molten), to produce an electrically conductive medium. ... Elasticity has meanings in two different fields: In physics and mechanical engineering, the theory of elasticity describes how a solid object moves and deforms in response to external stress. ... In physics, magnetism is a phenomenon by which materials exert an attractive or repulsive force on other materials. ... Johann Carl Friedrich Gauss (Gauß) (April 30, 1777 – February 23, 1855) was a German mathematician and scientist who contributed significantly to many fields, including number theory, analysis, differential geometry, geodesy, magnetism, astronomy and optics. ... Wilhelm Eduard Weber (October 24, 1804 - June 23, 1891) was a noted physicist. ...

Friedrich Wilhelm Georg Kohlrausch was born on October 14, 1840, in Rinteln, Germany. After studying physics at Erlangen and Göttingen, Friedrich Kohlrausch completed his doctorate in Göttingen. After a two-year work as a lecturer at the University of Frankfurt/Main, Kohlrausch was appointed a professor of physics at the University of Göttingen (1866-70). Weser watershed Rinteln is a small town in Lower Saxony, Germany. ... Erlangen around 1915 Erlangen is a German city in Middle Franconia. ... Landmark Gänseliesel fountain at the main market Göttingen (   listen?) is a city in Lower Saxony, Germany. ... Landmark Gänseliesel fountain at the main market Göttingen (   listen?) is a city in Lower Saxony, Germany. ... ... The Georg-August University of Göttingen (Georg-August-Universität Göttingen, often called the Georgia Augusta) was founded in 1734 by George II, King of Great Britain and Elector of Hanover, and opened in 1737. ...

In the Universitiy of Göttingen he performed the practical experiments that resulted in the book "Leitfaden der praktischen Physik" (Guidelines to Practical Physics) which was published in 1870 as the first book of this type in Germany. It contained not only descriptions of experiments, experimental setups and measuring techniques, but also tables of physical quantities. To this very day, the textbook "Praktische Physik" (Practical Physics), which originated in Friedrich Kohlrausch's "Leitfaden der praktischen Physik", is standard reading for physicists and engineers in Germany. This is attributable, above all, to the detailed descriptions provided of the precision measuring methods that form the basis of technical and experimental applications in a wide diversity of fields in physics.

In 1870 Kohlrausch became a professor at the University of Zurich in Switzerland. One year later, he moved to the Darmstadt University of Technology in Germany. In 1874 he demonstrated that an electrolyte has a definite and constant amount of electrical resistance. By observing the dependence of conductivity upon dilution, he could determine the transfer velocities of the ions (charged atoms or molecules) in solution. The University of Zurich (in German: Universität Zürich) is the largest university of Switzerland, in the city of Zurich. ... The Darmstadt University of Technology in Darmstadt, Germany plays a sigificant role among german universities. ...

Kohlrausch's research was centered on determining how electricity was conducted in solutions. In his investigations to establish whether Ohm's law also applied to second class conductors, he was the first scientist to utilize alternating current. In this way, he prevented the deposition of decomposition products on the electrodes and obtained highly precise results in his measurements. He used a telephone to monitor the process. The result was that Ohm's law also found to apply to dissolved electrolytes. From 1875 to 1879, he examined numerous salt solutions, acids and solutions of other materials. His efforts resulted in the law of the independent migration of ions, that is, each type of migrating ion has a specific resistance no matter what its original molecular combination may have been, and therefore that a solution's electrical resistance was due only to the migrating ions of a given substances. Kohlrausch suggested that the more dilute a solution, the greater its conductivity. (This can't be right ... the single-ion contribution to a solution's conductivity will go increase in more dilute solutions but the total solution conductivity will, of course, go down). Ohms law, named after its discoverer Georg Ohm [1], states that the potential difference or Voltage drop V between the ends of a conductor (for example, a resistor R) and the current, (I) flowing through R are proportional at a given temperature: where V is the voltage and I... Ohms law, named after its discoverer Georg Ohm [1], states that the potential difference or Voltage drop V between the ends of a conductor (for example, a resistor R) and the current, (I) flowing through R are proportional at a given temperature: where V is the voltage and I...

In 1875 he responded to a call from the University of Würzburg in southern Germany, where he subsequently conducted his experiments on electrical quantity determination and the conductivity of electrolytes. From 1888 he researched and taught at Strasbourg University. He turned down a professorship at the Humboldt University in Berlin in 1894. In 1895 he succeeded Hermann von Helmholtz as President of the Physikalisch-Technische Reichsanstalt (PTR – Imperial Physical Technical Institute), an office which he held until 1905. Here, as in the past, his activities were focused on experimental and instrumental physics: he constructed instruments and devised new measuring techniques to examine electrolytic conduction in solutions. He concluded the setup of the PTR, a task which had not yet been completed on the death of its first president. He introduced fixed regulations, work schedules and working hours for the institute. From 1900 he was also a professor at Humboldt University. The University of Würzburg is a university in Würzburg, Germany, founded in 1402. ... The University Palace in Strasbourg, and a monument to one of the universitys students, Johann Wolfgang Goethe The University of Strasbourg in Strasbourg, Alsace, France, is divided into three separate institutions. ... Alternative meaning: Humboldt State University, located in Arcata, California Humboldt-Universität zu Berlin The Humboldt University of Berlin (German Humboldt-Universität zu Berlin) is the successor to Berlins oldest university, the Friedrich Wilhelm University (Friedrich-Wilhelms-Universität), founded in 1810 by the liberal Prussian educational reformer...   Berlin? (pronounced: , German ) is the capital of Germany and its largest city, with 3,426,000 inhabitants (as of January 2005); down from 4. ... Hermann von Helmholtz Hermann Ludwig Ferdinand von Helmholtz (August 31, 1821 – September 8, 1894) was a German physician and physicist. ... Alternative meaning: Humboldt State University, located in Arcata, California Humboldt-Universität zu Berlin The Humboldt University of Berlin (German Humboldt-Universität zu Berlin) is the successor to Berlins oldest university, the Friedrich Wilhelm University (Friedrich-Wilhelms-Universität), founded in 1810 by the liberal Prussian educational reformer...

Under direction of Kohlrausch "Physikalisch-Technische Reichsanstalt" (the Imperial Physical Technical Institute in Germany) created numerous standards and calibration standards which were also used internationally outside Germany.

Kohlrausch was intent on creating optimum working conditions in the laboratories and to shield the labs from disturbing external influences. For six years, for instance, he fought against a streetcar line which was due to be laid near the PTR. However, before the streetcar was to make its first journey, the institute succeeded in developing an astatic torsion magnetometer which was uninfluenced by disturbing electromagnetic fields. The use of this instrument and the shielded wire galvanometer developed by du Bois and Rubens meant that precision electrical and magnetic work continued to be possible. William Edward Burghardt DuBois (February 23, 1868 - August 27, 1963) was an African-American civil rights leader and scholar. ...

Over the years, Kohlrausch added experiments which met the needs of physical chemistry and electrical technology in particular. He improved precision measuring instruments and developed numerous measuring methods in almost all of the fields of physics known during his lifetime, including a reflectivity meter, a tangent galvanometer, and various types of magnetometers and dynamometers. The Kohlrausch bridge, which he invented at that time for the purpose of measuring conductivity, is still well known today.

Like Helmholtz and Siemens, Kohlrausch also saw the possibilities inherent in applied and basic research in the natural sciences and technology. He lay the foundations for scientific knowledge which promoted and advanced industry and technology. The PTR developed standardized precision instruments for university research institutes and industrial laboratories. It introduced uniform electrical units for Germany and also played a significant role in their international usage. In the period to 1905, there were many examples of the importance of the PTR for German industry, in particular for the high technologies of the time – the electrical, optical and mechanical industries. Hermann Ludwig Ferdinand von Helmholtz (August 31, 1821 – September 8, 1894) was a German physician and physicist. ...

Overall, Kohlrausch was involved in the measurement of electrical, magnetic and electrochemical phenomena for almost 50 years. In 1905 Kohlrausch retired from his post as President of the PTR.

Finally, Kohlrausch was a pivotal figure in the history of electrochemistry for many reasons. First, the experiments from which he deduced his law of independent migration of ions became canonical and disseminated from Kohlrausch's laboratories in Gottingen, Zurich, and Darmstadt; Arrhenius, Wilhelm Ostwald and Jacobus Henricus van 't Hoff, the original Ionists, all trained with methods and equipment of Kohlrauschian lineage. Moreover, because Kohlrausch also continued to test and confirm the Ionist theory after it had been first proposed, his work tied "measuring physics" and its consequent capability of producing plenty of empirical data to the results and methods of the Ionists and their followers. Map of Germany showing Göttingen 1 External links Coat of Arms University of Göttingen Top: The old Auditorium Maximum (1862-65) Bottom: New library building Göttingen is a city in Lower Saxony, Germany. ... General view showing Grossmünster church. ... Map of Germany showing Darmstadt Darmstadt is a city in the Bundesland (federal state) of Hesse in Germany. ... Svante August Arrhenius (February 19, 1859 – October 2, 1927) was a Swedish chemist and one of the founders of the science of physical chemistry. ... Wilhelm Ostwald Friedrich Wilhelm Ostwald (commonly just Wilhelm Ostwald) (September 2, 1853 - April 4, 1932) was a German chemist. ... Jacobus Henricus van t Hoff (August 30, 1852 - March 1, 1911) was a Dutch physical and organic chemist and the winner of the inaugural Nobel Prize in Chemistry. ...

External links

• Friedrich Kohlrausch biography and formulae