Hans Christian Ørsted

"Ørsted" redirects here. For other uses, see Ørsted (disambiguation).

Hans Christian Ørsted
Danish physicist & chemist
Born	(1777-08-14)14 August 1777 Rudkøbing, Denmark
Died	9 March 1851(1851-03-09) (aged 73) Copenhagen, Denmark
Nationality	Danish
Fields	Physics, chemistry
Institutions	University of Copenhagen
Alma mater	University of Copenhagen (Ph.D) (1799)
Known for	Discovery of electromagnetism
Influences	Immanuel Kant
Notable awards	Copley Medal (1820)
Signature

Hans Christian Ørsted (/ˈɜrstɛd/; Danish: [ˈhanˀs ˈkʰʁæsd̥jan ˈɶɐ̯sd̥ɛð]; often rendered Oersted in English; 14 August 1777 – 9 March 1851) was a Danish physicist and chemist who discovered that electric currents create magnetic fields, an important aspect of electromagnetism. He shaped post-Kantian philosophy and advances in science throughout the late 19th century.

In 1824, Ørsted founded Selskabet for Naturlærens Udbredelse (SNU), a society to disseminate knowledge of the natural sciences. He was also the founder of predecessor organizations which eventually became the Danish Meteorological Institute and the Danish Patent and Trademark Office. Ørsted was the first modern thinker to explicitly describe and name the thought experiment.

A leader of the so-called Danish Golden Age, Ørsted was a close friend of Hans Christian Andersen and the brother of politician and jurist Anders Sandøe Ørsted, who eventually served as Danish prime minister (1853–54).

The oersted (Oe), the cgs unit of magnetic H-field strength, is named after him.

Early life and studies

The young H.C. Ørsted

Ørsted was born in Rudkøbing. As a young boy Ørsted developed his interest in science while working for his father, who owned a pharmacy. He and his brother Anders received most of their early education through self-study at home, going to Copenhagen in 1793 to take entrance exams for the University of Copenhagen, where both brothers excelled academically. By 1796 Ørsted had been awarded honors for his papers in both aesthetics and physics. He earned his doctorate in 1799 for a dissertation based on the works of Kant entitled "The Architectonics of Natural Metaphysics".

In 1801 Ørsted received a travel scholarship and public grant which enabled him to spend three years travelling across Europe. In Germany he met Johann Wilhelm Ritter, a physicist who believed there was a connection between electricity and magnetism. This made sense to Ørsted since he believed in Kantian ideas about the unity of nature and that deep relationships existed between natural phenomena.

Their conversations drew Ørsted into the study of physics. He became a professor at the University of Copenhagen in 1806 and continued his research with electric currents and acoustics. Under his guidance the University developed a comprehensive physics and chemistry program and established new laboratories.

In 1800, Alessandro Volta discovered a galvanic battery inspiring Ørsted to think about the nature of electricity and to conduct his first electrical experiments. Between 1800 to 1803, he visited to Germany, France and Holland for lectures. He again visited Germany and France in 1812 after publishing a manual called Videnskaben om Naturens Almindelige Love and Første Indledning til den Almindelige Naturlære (1811). In Berlin he wrote his famous essay on the identity of chemical and electrical forces in which he first stated the connection existing between magnetism and electricity. Then, in Paris he translated that essay in Latin with Marcel de Serres.

The Royal Society of London gave him the Copley Medal and the French Academy awarded him with 3,000 gold francs. Ørsted was just 43 when he made this great discovery. He established the Royal Polytechnic Institute in 1829 of which he was the first director.

Electromagnetism

A compass needle with a wire, showing the effect Oersted discovered.

Statue of Ørsted in Ørstedsparken, in Copenhagen.

On 21 April 1820, during a lecture, Ørsted noticed a compass needle deflected from magnetic north when an electric current from a battery was switched on and off, confirming a direct relationship between electricity and magnetism. His initial interpretation was that magnetic effects radiate from all sides of a wire carrying an electric current, as do light and heat. Three months later he began more intensive investigations and soon thereafter published his findings, showing that an electric current produces a circular magnetic field as it flows through a wire. This discovery was not due to mere chance, since Ørsted had been looking for a relation between electricity and magnetism for several years. The special symmetry of the phenomenon was possibly one of the difficulties that retarded the discovery.

It is sometimes claimed that Italian Gian Domenico Romagnosi was the first person who found a relationship between electricity and magnetism, about two decades before Ørsted's 1820 discovery of electromagnetism. Romagnosi's experiments showed that an electric current from a voltaic pile could deflect a magnetic needle. His researches were published in two Italian newspapers and were largely overlooked by the scientific community.

Ørsted's findings stirred much research into electrodynamics throughout the scientific community, influencing French physicist André-Marie Ampère's developments of a single mathematical formula to represent the magnetic forces between current-carrying conductors. Ørsted's work also represented a major step toward a unified concept of energy.

In 1822, he was elected a foreign member of the Royal Swedish Academy of Sciences.

Later years

In 1825, Ørsted made a significant contribution to chemistry by producing aluminium for the first time. While an aluminium-iron alloy had previously been developed by British scientist and inventor Humphry Davy, Ørsted was the first to isolate the element via a reduction of aluminium chloride.

In 1829, Ørsted founded Den Polytekniske Læreanstalt ('College of Advanced Technology') which was later renamed the Technical University of Denmark (DTU).

Ørsted died at Copenhagen in 1851, aged 73, and was buried in the Assistens Cemetery in the same city.

Legacy

The centimetre-gram-second system (CGS) unit of magnetic induction (oersted) is named for his contributions to the field of electromagnetism.

The 100 danske kroner note issued from 1950 to 1970 carried an engraving of Ørsted. The buildings that are home to the Department of Chemistry and the Institute for Mathematical Sciences at the University of Copenhagen are named The H.C. Ørsted Institute, after him. The first Danish satellite, launched 1999, was named after Ørsted. Two medals are awarded in Ørsted's name: the Oersted Medal for notable contributions in the teaching of physics in America, awarded by American Association of Physics Teachers, along with the H. C. Ørsted Medal for Danish scientists, awarded by the Danish Selskabet for Naturlærens Udbredelse (Society for the Dissemination of Natural Science), which Ørsted founded. The H.C. Ørsted Lectureship is awarded to two prominent researchers annually, and has been bestowed upon the following scientists:

Upcoming H.C. Ørsted Lecture : Dr. Jack Connerney, NASA Goddard Space Flight Center, USA : "Mars Crustal Magnetism: Through The Lens Sharply"

Previous H.C. Ørsted Lecturers:

• Professor Michaël Grätzel, École Polytechnique Fédérale de Lausanne, EPFL
• Professor Pierre-Gilles de Gennes, Collège de France, Nobel Laureate in Physics
• Professor Ivar Giaever, Rensselaer Polytechnic Institute, Nobel Laureate in Physics
• Professor Paul F. Hoffman, Sturgis Hooper Professor of Geology, Harvard University
• Professor Leroy Hood, William Gates III Professor, Institute for Systems Biology
• Professor Sir Harold Kroto, University of Sussex, Nobel Laureate in Chemistry
• Professor Hugo de Man, Catholic University of Leuven
• Professor Sir Roger Penrose, University of Oxford
• Professor Julius Rebek, Skaggs Institute for Chemical Biology at The Scripps Research Institute
• Professor Cees Dekker, Nanophysics, TU Delft
• Professor Subra Suresh, Materials Science and Biological Engineering, MIT
• Professor Peter Greenberg, Microbiology, University of Washington
• Honorary Professor Sir John Meurig Thomas, University of Cambridge
• Professor Ahmed Zewail, California Institute of Technology, Nobel Laureate in Chemistry
• Professor Nathan S. Lewis, Chemistry, California Institute of Technology
• Professor Sajeev John, University of Toronto
• Professor Howard A. Stone, Fluid Mechanics, Princeton University
• Mallinckrodt Professor of Physics and of Applied Physics Lene Vestergaard Hau, Harvard University
• Professor Stanley N. Cohen, School of Medicine, Stanford University
• Professor Juan de Pablo, Chemical Engineering, University of Wisconsin-Madison
• Professor Mario Molina, University of California San Diego, Nobel Prize Winner.

Writings

Ørsted was a published writer and poet. His poetry series Luftskibet ("The Airship") was inspired by the balloon flights of fellow physicist and stage magician Étienne-Gaspard Robert. Shortly before his death, he submitted a collection of articles for publication under the title "The Soul in Nature". The book presents Ørsted's life philosophy and views on a wide variety of issues.

See also

• Oersted's law
• James Clerk Maxwell
• Thought experiment

Further reading

• Brain, R. M. et al. (2007). Hans Christian Ørsted and the Romantic Legacy in Science. Ideas, Disciplines, Practices. Boston Studies in the Philosophy of Science, 241. Dordrecht. pp. 273–338. 
• Christensen, D. C. (2013). Hans Christian Ørsted. Oxford: Oxford University Press. ISBN 978-0-19-966926-4. 
• Dibner, Bern, Oersted and the discovery of electromagnetism, New York, Blaisdell (1962).
• Ole Immanuel Franksen, H. C. Ørsted – a man of the two cultures, Strandbergs Forlag, Birkerød, Denmark (1981). (Note: Both the original Latin version and the English translation of his 1820 paper "Experiments on the effect of a current of electricity on the magnetic needle" can be found in this book.)

External links

• Media related to Hans Christian Ørsted at Wikimedia Commons
• Physics Tree: Hans Christian Ørsted Details
• Interactive Java Tutorial on Oersted's Compass Experiment National High Magnetic Field Laboratory
• The soul in nature : with supplementary contributions, London: H. G. Bohn, 1852.
• Hans Christian Ørsted at Find a Grave
•  "Oersted, Hans Christian". Encyclopedia Americana. 1920.