174 years ago today, on March 9, 1851 (February 7, 1851 lunar calendar), the Danish physicist, chemist, and discoverer of the magnetic effect of electric current Oster died. Oster (HansChristianOersted; 1777-1851) died on March 9, 1851, Hans Christian Oster, Danish physicist, chemist, and discoverer of the magnetic effect of electric current Danish physicist. Born on August 14, 1777 in a family of pharmacists in Rudjobin, Langerang Island. 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. In 1806, he became a professor of physics at the University of Copenhagen and a permanent secretary of the Royal Danish Society in 1815. In 1820, he was awarded the Copley Medal of the Royal Society for his outstanding discovery of the magnetic effect of electric currents. In 1829, he became the dean of the Copenhagen Institute of Technology. He died in Copenhagen on March 9, 1851. He has conducted many studies on physics, chemistry and philosophy. Due to the influence of Kant's philosophy and Schelling's natural philosophy, he firmly believes that natural forces can be transformed into each other, and has long explored the connection between electricity and magnetism. In April 1820, he finally discovered the effect of electric current on magnetic needles, that is, the magnetic effect of electric currents. On July 21 of the same year, he published his findings under the title "Experiments on the effect of electrical conflict on magnetic needles". This short paper caused a great shock in the European physics community, leading to a large number of experimental results, which opened up a new field of physics - electromagnetism. He first proposed the idea of the connection between light and electromagnetism in 1812. In 1822 he conducted experimental studies on the compressibility of liquids and gases. Aluminum was refined in 1825, but the purity was not high. In acoustic research, he tried to discover the electrical phenomena caused by sound. His last research work was on diamagnetism. He was a teacher who was enthusiastic about scientific research and experimentation. He said: "I don't like dry lectures without experiments. All scientific research begins with experiments." Therefore, he was popular with students. He was also a distinguished lecturer and popularizer of natural sciences. In 1824, he initiated the establishment of the Danish Association for the Advancement of Science, which created the first physics laboratory in Denmark. In 1908, the Danish Association for the Advancement of Natural Sciences established the "Auster Medal" to recognize physicists who have made significant contributions. In 1934, the magnetic field intensity unit in the CGS unit system was named after "Auster". In 1937, the American Association of Physics Teachers established the "Auster Medal" to reward physics teachers who have made contributions to the teaching of physics.