Hans Christian Ørsted (Danish: [ˈɶɐ̯steð]; August 14, 1777 – March 9, 1851), sometimes spelled Oersted, was a Danish chemist and physicist. He discovered that electric currents produce magnetic fields. This discovery is called Oersted's law. He also identified aluminum, a chemical element.

Ørsted was a key figure during the Danish Golden Age. He was friends with Hans Christian Andersen and the brother of Anders Sandøe Ørsted, a politician and jurist who served as Prime Minister of Denmark from 1853 to 1854.

Early life and studies

Hans Christian Ørsted was born in Rudkøbing, Denmark, in 1777. As a young boy, he became interested in science while working with his father, who was a pharmacist at the town's pharmacy. He and his brother, Anders, mostly studied at home and did not attend school regularly. In 1793, both brothers traveled to Copenhagen to take exams for the University of Copenhagen, where they both performed well academically. By 1796, Ørsted had received recognition for his writings on aesthetics and physics. He earned his doctorate in 1799 for a dissertation about the works of the philosopher Immanuel Kant, titled The Architectonics of Natural Metaphysics.

In 1800, Alessandro Volta, an Italian scientist, announced his invention of the voltaic pile, a device that produced electricity. This inspired Ørsted to study electricity and begin his first experiments in the field. In 1801, Ørsted received a scholarship and public grant that allowed him to travel across Europe for three years. During this time, he visited science centers in cities like Berlin and Paris.

In Germany, Ørsted met Johann Wilhelm Ritter, a physicist who believed electricity and magnetism were connected. This idea aligned with Ørsted’s belief, influenced by Kant’s philosophy, that all parts of nature are linked. These discussions encouraged Ørsted to focus on physics. In 1806, he became a professor at the University of Copenhagen, where he continued researching electric currents and sound. Under his leadership, the university created strong programs in physics and chemistry and built new laboratories.

In autumn 1806, Ørsted invited William Christopher Zeise to live in his home. He gave Zeise a job as a teaching assistant and helped train him in chemistry. In 1812, Ørsted returned to Germany and France after publishing two books: Videnskaben om Naturens Almindelige Love and Første Indledning til den Almindelige Naturlære (1811).

Ørsted was the first modern scientist to clearly describe and name the concept of a thought experiment. He used the Latin-German term Gedankenexperiment around 1812 and the German term Gedankenversuch in 1820.

In 1819, Ørsted became the first person to isolate and name the chemical compound piperine. He extracted it from Piper nigrum, the plant used to make both black and white pepper.

In 1822, Ørsted designed a new type of instrument called a piezometer to measure how much liquids can be compressed.

Electromagnetism

In 1820, Ørsted shared his discovery that a compass needle moved away from magnetic north when near an electric current, proving electricity and magnetism are connected. The story that he found this during a lecture is not true. He had been trying to find a link between electricity and magnetism since 1818 but was puzzled by his early results.

At first, he thought magnetic effects spread out from a wire like light and heat. Three months later, he studied more carefully and showed that an electric current creates a circular magnetic field around a wire. For this discovery, the Royal Society of London gave him the Copley Medal in 1820, and the French Academy gave him 3,000 francs.

Ørsted’s work encouraged scientists to study electrodynamics. It helped French physicist André-Marie Ampère create a formula to describe magnetic forces between wires carrying electricity. His research also helped scientists move closer to understanding energy as a single idea.

Ørsted’s findings led to new ways of sending messages, like the electric telegraph. Mathematician Pierre-Simon Laplace suggested this idea soon after Ørsted’s discovery, and Ampère wrote about it the same year. However, it took nearly 20 years for the telegraph to become widely used.

Later years

Ørsted was chosen as a member of the Royal Society of Edinburgh in March 1821, a member from another country of the Royal Society of London in April 1821, a member from another country of the Royal Swedish Academy of Sciences in 1822, a member of the American Philosophical Society in 1829, and a member from another country of the American Academy of Arts and Sciences in 1849.

He started the Selskabet for Naturlærens Udbredelse (Society for the Dissemination of Natural Science, SNU) in 1824. He also helped create earlier groups that later became the Danish Meteorological Institute and the Danish Patent and Trademark Office. In 1829, Ørsted founded Den Polytekniske Læreanstalt (College of Advanced Technology), which was later renamed the Technical University of Denmark (DTU).

In 1824, Ørsted made an important discovery in chemistry by being the first person to create aluminum in its metal form, though the metal was not very pure. In 1808, Humphry Davy predicted the existence of the metal and named it "alumium." His attempts to separate it using a method involving electricity were not successful, and he only created a mix of aluminum and iron. Ørsted separated the metal by mixing aluminum chloride with a mix of potassium and mercury, then boiling away the mercury, leaving small pieces of metal that looked like tin. He shared his findings and a sample of the metal at meetings of the Danish Academy of Sciences in early 1825. However, he seemed to think his discovery was not very important. Because few people read the journal where his results were published, most scientists did not notice his work at the time. In 1827, Ørsted allowed his friend, the German chemist Friedrich Wöhler, to continue the research. Wöhler created about 30 grams (1.1 ounces) of aluminum powder soon after using his own method and later produced enough solid metal to study its physical properties in 1845.

Ørsted died in Copenhagen in 1851 at the age of 73 and was buried there in the Assistens Cemetery.

Legacy

The CGS unit of magnetic induction, called the oersted, is named after Hans Christian Ørsted for his work in electromagnetism.

The company Danish Oil and Natural Gas (DONG) changed its name to Ørsted to show its shift from using fossil fuels to becoming a major company in offshore wind energy.

Denmark’s first satellite, launched in 1999, was named after Ørsted.

Ørsted Park in Copenhagen was named after Ørsted and his brother in 1879. Streets named H. C. Ørsteds Vej in Frederiksberg and H. C. Ørsteds Allé in Galten are also named after him.

The buildings housing the Department of Chemistry and the Institute for Mathematical Sciences at the University of Copenhagen’s North Campus are called the H.C. Ørsted Institute, named after him. A dormitory named H. C. Ørsted Kollegiet is located in Odense.

A statue of Hans Christian Ørsted was placed in Ørsted Park in 1880. A plaque is displayed above the gate of the building in Studiestræde where he lived and worked.

In 1885, a statue of Ørsted was placed in the Oxford University Museum of Natural History.

Ørsted’s image appeared on two Danish banknotes: first on 500 kroner notes from 1875, and later on 100 kroner notes between 1962 and 1974.

Two medals are given in Ørsted’s name: the H. C. Ørsted Medal for Danish scientists, awarded by the Danish Society for the Dissemination of Natural Science (SNU), and the Oersted Medal for outstanding contributions to physics teaching in America, awarded by the American Association of Physics Teachers.

The Technical University of Denmark hosts the H. C. Ørsted Lecture series, which invites well-known researchers from around the world.

Works

Hans Christian Ørsted was both a scientist and a poet. His poetry series, Luftskibet ("The Airship"), was inspired by the balloon flights of another physicist and magician, Étienne-Gaspard Robert.

• Ørsted, H. C. (1836). Luftskibet, et Digt [The Airship, a Poem] (in Danish). København: Gyldendal. OCLC 28930872.

In 1850, shortly before his death, Ørsted prepared for publication a two-volume collection of philosophical articles in German titled Der Geist in der Natur ("The Soul in Nature"). This work was translated into English and published in one volume in 1852, the year after his death.

• Ørsted, H. C. (1850–1851). Der Geist in der Natur [The Soul in Nature] (in German). München: J. G. Cotta. OCLC 653954. —— (1852). The Soul in Nature, with Supplementary Contributions. Bohn's scientific library [16]. Translated by Horner, L.; Horner, J. B. London: Henry G. Bohn. hdl: 2027/loc.ark:/13960/t4zg7w20q. OCLC 8719272.

• Ørsted, H. C. (1807). "Betragtninger over Chemiens Historie" [Considerations on the History of Chemistry]. Det Skandinaviske Litteraturselskabs Skrifter (in Danish). 2. København: Andreas Seidelin: 1–54. OCLC 872505637.
• —— (1809). Videnskaben om Naturens almindelige Love [The Science of the General Laws of Nature] (in Danish). København: Fr. Brummer. OCLC 488860438.
• —— (1812). Ansicht der chemischen Naturgesetze, durch die neuern Entdeckungen gewonnen [View of the Chemical Laws of Nature Gained Through Recent Discoveries] (in German). Berlin: Realschulbuchhandlung. OCLC 28640794.
• —— (1814). Imod den store Anklager [Against the Great Accuser] (in Danish). København: Andreas Seidelin. OCLC 19092207.
• —— (1820). "Experiments on the Effect of a Current of Electricity on the Magnetic Needle". In Thomson, T. (ed.). Annals of Philosophy; or, Magazine of Chemistry, Mineralogy, Mechanics, Natural History, Agriculture, and the Arts. Vol. XVI. London: Baldwin, Cradock, and Joy. pp. 273–276. hdl: 2027/osu.32435051156651. OCLC 9529852.
• —— (1844). Naturlærens mechaniske Deel [The Mechanical Part of Natural Learning] (in Danish). København: C. A. Reitzel. hdl: 2027/njp.32101058433184. OCLC 22224906.
• —— (1851). Der mechanische Theil der Naturlehre [The Mechanical Part of Natural Learning] (in German). Braunschweig: Friedrich Vieweg und Sohn. OCLC 9489733. OL 6960604M.
• Harding, M. C., ed. (1920). Correspondance de H. C. Örsted avec divers savants [The Correspondence of H. C. Örsted with Various Scholars]. Copenhaugue: H. Aschehoug & Co. OCLC 11070734. Volume I, containing correspondence with Jöns Jacob Berzelius, Christopher Hansteen, and Christian Samuel Weiss. Volume II, containing correspondence with Johann Wilhelm Ritter and numerous others, including Michael Faraday and Carl Friedrich Gauss.

A significant number of Ørsted's papers were made available in English for the first time in a compilation published in 1998:

• Ørsted, H. C. (1998). Selected Scientific Works of Hans Christian Ørsted. Edited by Jelved, K.; Jackson, A. D.; Knudsen, O. Princeton University Press. ISBN 978-0-69104-334-0. JSTOR j.ctt7zvhx2. OCLC 36393437.