August 29: Faraday Demonstrated Electromagnetic Induction

On August 29, 1831 English scientist Michael Faraday first made one of the most consequential experimental discoveries in the history of physics: he demonstrated that a changing magnetic field could generate an electrical current. This principle is known as electromagnetic induction and is the foundational mechanism behind every electric generator, transformer, and electric motor on the planet. Every time you charge your phone, turn on a light, or use an electric appliance, Faraday’s transformational discovery is in play.

Who was Michael Faraday?

Faraday was born in 1791 into a poor family in London and received almost no formal schooling. At thirteen, he was apprenticed to a bookbinder, where his mind was first cultivated. Every book that came through the shop — he read. Soon, Faraday fell in love with science and became captivated by the work of the electrochemist Humphry Davy. At 21, he wrote to Davy asking for a job. Davy eventually hired him as a laboratory assistant at the Royal Institution, and Faraday never left.

Faraday had no mathematical training to speak of, but did have an intense sense of intellectual curiosity. His experimental insights were incredible, but he lacked the ability to express them in equations. James Clerk Maxwell, a Scottish physicist and mathematician, would later refine and mathematically formalize Faraday's discoveries into what became Maxwell's equations, which are now the framework of electromagnetism.

What it made possible

Although the implications of this discovery were substantial, their full scope took decades to realize (as is typical with science). Faraday himself built the first rudimentary electric generator and the first electric transformer based on his discovery. Later engineers used these principles to build the dynamos and generators that powered the industrial age and civilization today. Now, the process that Faraday demonstrated has been used to convert mechanical energy into electricity in all kinds of machinery — like nuclear power plants, wind turbines, and hydroelectric dams.

Not only did Faraday discover electromagnetic induction, but also introduced the concept of the magnetic field and field lines, which is a way to visualize how forces that are invisible to the eye act through space. This, too, also acts as one of the key conceptual tools of modern physics. While Faraday did not receive any formal academic honors in his lifetime and turned down a knighthood, he is widely regarded as one of the most outstanding physicists in history.