IN CONTEXT
Physics
1600 William Gilbert conducts the first scientific experiments on electricity and magnetism.
1800 Alessandro Volta creates the first electric battery.
1820 André-Marie Ampère develops a mathematical theory of electromagnetism.
1821 Michael Faraday is able to show electromagnetic rotation in action, by creating the first electric motor.
1831 Faraday and US scientist Joseph Henry independently discover electromagnetic induction; Faraday uses it in the first generator to convert motion into electricity.
1864 James Clerk Maxwell formulates a set of equations to describe electromagnetic waves – including light waves.
The quest to discover an underlying unity to all forces and matter is as old as science itself, but the first big break came in 1820, when the Danish philosopher Hans Christian Ørsted found a link between magnetism and electricity. The link had been suggested to him by the German chemist and physicist Johann Wilhelm Ritter, whom he had met in 1801. Already influenced by the philosopher Immanuel Kant’s idea that there is a unity to nature, Ørsted now investigated the possibility in earnest.
"It appears that the electric conflict is not restricted to the conducting wire, but that it has a rather extended sphere of activity around it."
Hans Christian Ørsted
Chance discovery
Lecturing at the University of Copenhagen, Ørsted wanted to show his students how the electric current from a voltaic pile (the battery invented by Alessandro Volta in 1800) can heat up a wire and make it glow. He noticed that a compass needle standing near the wire moved every time the current was switched on. This was the first proof of a link between electricity and magnetism. Further study convinced him that the current produced a circular magnetic field as it flowed through the wire.
Ørsted’s discovery rapidly prompted scientists across Europe to investigate electromagnetism. Later that year, French physicist André-Marie Ampère formulated a mathematical theory for the new phenomenon and, in 1821, Michael Faraday demonstrated that electromagnetic force could convert electrical into mechanical energy.
See also: William Gilbert • Alessandro Volta • Michael Faraday • James Clerk Maxwell