Hans Christian Oersted Biography

World of Scientific Discovery on Hans Christian Oersted

The son of a pharmacist, Hans Oersted was born on August 14, 1777, in Rudkjöbing, Langeland, Denmark. He began training to follow in his father's footsteps, but instead of continuing on to a career solely in chemistry, he chose to become a physicist. He received a Ph.D. in 1799 at the University of Copenhagen for his dissertation on the philosophy of Immanuel Kant (1724-1804). After traveling through Europe, he returned to the University in 1806 and was appointed professor of physics and chemistry.

In 1800 Oersted had learned of Alessandro Volta's invention of the electric battery (or "voltaic pile") and, like many experimenters of that period, became interested in electrical phenomena. Discovering a connection between electricity and magnetism was of special interest to scientists at that time. As early as 1813, Oersted had predicted there was a relationship between the two, but he based his prediction on philosophical grounds, not as a result of scientific experimentation.

Oersted's great claim to fame occurred in 1819. During one of his class demonstrations, Oersted connected a battery and a wire to conduct electricity, then brought a magnetic needle close to the apparatus and looked for some interaction. He was rewarded with a slight deflection of the magnetic needle. Oersted was overjoyed; here was the first definite proof that electricity had a magnetic field. However, Oersted delayed publishing the results of his experiment until he could investigate more fully.

By moving his compass needle around the wire, Oersted discovered that the magnetic field was circular, and the needle always pointed at a right angle to the field. He also discovered that reversing the flow of the electric current attracted the opposite side of the needle. Finally, in July 1820, Oersted published his discovery, but he neglected to do any further work on the subject.

Undoubtedly, Oersted was still very interested in the subject of electromagnetism, but the publication of his discovery had resulted in a flurry of activity by the likes of Dominique-Françios Arago, André Ampère, Michael Faraday, and Joseph Henry. Oersted may have felt unable to compete with such illustrious people. The only other work he did on the subject was to show that the magnetic influence of the electrical current penetrated glass and other nonmagnetic substances.

Following his momentous discovery, Oersted turned his attention to compressing gases and liquids, inventing a device that could determine their compressibility. He also studied thermoelectricity, created metallic aluminum, and isolated piperidine, an organic compound.

Oersted died on March 9, 1851, in Copenhagen. He had essentially established the study of electromagnetism, and he was honored for his contribution in 1934 when the unit for the strength of a magnetic field was named the "oersted."