248 years ago today, August 14, 1777 (July 12, 1777 in the lunar calendar), Danish physicist Hans Christian Oster was born. HansChristian Oster Rsted, August 14, 1777-March 9, 1851) was a Danish physicist, chemist, and discoverer of the current magnetic effect. Born on August 14, 1777, in the family of pharmacists in Rude Jobin, Langeland. He was admitted to the University of Copenhagen in 1794 and received his doctorate in 1799. From 1801 to 1803, he visited Germany, France and other countries and met many physicists and chemists. He has been professor of physics at the University of Copenhagen since 1806 and permanent secretary of the Royal Danish Society since 1815. In 1820, he was awarded the Copley Medal of the Royal Society for the outstanding discovery of the current magnetic effect. Since 1829, he has served as president of the Copenhagen Institute of Technology. He died on March 9, 1851 in Copenhagen. He has conducted many aspects of physics, chemistry and philosophy. Influenced by Kant's philosophy and Schelling's natural philosophy, he firmly believed that natural forces could transform each other and explored the connection between electricity and magnetism for a long time. In April 1820, the effect of current on the magnetic needle, that is, the magnetic effect of current, was finally discovered. On July 21 of the same year, he published his findings under the title "Experiment on the Effect of Electric Conflict on Magnetic Needle." This short paper caused a great shock to the European physics community and led to the emergence of a large number of experimental results, thus opening up a new field of physics-electromagnetism. He is an enthusiastic teacher who values scientific research and experiments. He said: "I don't like boring lectures without experiments. All scientific research starts with experiments." Therefore, it is welcomed by students. He was also an outstanding speaker and popularization worker of natural sciences. In 1824, he initiated the establishment of the Danish Association for the Advancement of Science and created Denmark's first physics laboratory. In 1908, the Danish Association for the Advancement of Natural Sciences established the "Oster Medal" to recognize physicists who have made significant contributions. In 1934, the unit of magnetic field strength in the CGS system of units was named after "Oster". In 1937, the American Association of Physics Teachers established the "Oster Medal" to reward physics teachers who have made contributions to physics teaching. Comments: In the CGS system (centimeter-gram-second system), the unit of magnetic field strength is Oersted (Oe).