Hans Christian Ørsted

Whose Compass Needle Turned Sideways · Physicist & Chemist · 1777–1851

The Copenhagen professor who saw a compass needle move beside a live wire, spent three months trying to disprove it, and then showed that electricity and magnetism are the same power.

Who was Ørsted?

Hans Christian Ørsted was born in 1777 above his father's apothecary shop in Rudkøbing, in a town with no school worth attending, and was taught largely at home. He came to physics through the German Romantic philosophy of nature, which held that the apparently separate forces were expressions of one underlying unity — an idea most experimenters dismissed and which kept him looking for a connection between electricity and magnetism for years. In April 1820, during a lecture demonstration, he closed a circuit and a compass needle lying near the wire moved. He did not publish. For three months he built better wires, stronger voltaic piles and larger needles, and turned the wire above the needle and then below it. The needle did not point towards the wire or away from it: it set itself at RIGHT ANGLES to it, and reversed when the wire changed sides. The force was circular, which no known force was. In July 1820 he published four pages in Latin and sent them across Europe; within weeks Ampère in Paris had turned the result into mathematics, and within eleven years Faraday had completed the argument in the opposite direction. Ørsted also isolated aluminium for the first time in 1825, and founded the Danish society that still brings science to the public.

Major achievements

• Discovered in 1820 that an electric current produces a magnetic field around it
• Showed the magnetic force is circular, acting at right angles to the wire
• Spent three months attempting to destroy his own result before publishing it
• Published four pages in Latin that started electromagnetism across Europe
• Isolated aluminium for the first time, in 1825

Life in brief

• 1777 — Born in Rudkøbing: Above an apothecary's shop, in a town with no proper school.
• 1801 — Travels in Germany: Meets Ritter and the Romantic philosophers of nature.
• 1806 — Professor at Copenhagen: Begins looking for a link between electricity and magnetism.
• 1820 — The needle moves: During a lecture, a compass twitches beside a live wire in April.
• 1820 — Publishes in July: Four pages of Latin, after three months of trying to disprove himself.
• 1825 — Isolates aluminium: The first preparation of the metal.
• 1851 — Dies in Copenhagen: Having lived to see Faraday complete the argument.

Explore the life of Ørsted — five chapters

1. A Town With No School — Rudkøbing, and an education assembled from neighbours
2. The Needle Moves — A lecture in April 1820
3. At Right Angles — A force unlike any other force known
4. Four Pages of Latin — July 1820, and Europe in six weeks
5. Aluminium, and Science for Everybody — A first metal, a friendship, and a society that still exists

Read the five-chapter life of Hans Christian Ørsted →

Where Ørsted appears in your course

Hans Christian Ørsted has a genuine claim on 2 lessons of the Pearson Edexcel International GCSE science course built into Incandio:

• Induced Magnetism and Field Patterns — Physics: Every direction on this page is found with a plotting compass, and Ørsted is the person who established what a compass needle actually reports. In 1820 he found that a needle near a current-carrying wire does not point towards the wire or away from it but sets itself at right angles to it — a result so unexpected that he spent three months trying to destroy it before publishing. He is the right second figure here because he treated a small pivoted magnet as a scientific instrument rather than a navigation aid, and because he shows what it takes to trust a reading that contradicts what you expected to see.
• Electromagnets — Physics: Statement 6.8 is his discovery, made in front of a class in April 1820. What makes him worth asking is not the moment but what followed it: he did not publish for three months, because he distrusted the result and spent that time building stronger piles, larger needles and better wires, and turning the wire above the needle and then below it to see whether the effect would survive. It did, and the way it survived told him the force was circular. He is also the right person to ask about motivation, because he had been looking for a connection between electricity and magnetism for years on philosophical grounds before he found one.

Begin

• Start a conversation with Ørsted — a dramatised, historically grounded AI portrayal
• Read the Historical Brief
• Explore the life of Ørsted — five chapters
• Find your exam topics · Meet all 208 figures