1791: Michael Faraday is born. In his 76 years on the planet, the chemist-physicist will make fundamental contributions to our understanding of electricity and magnetism, advise governments and establish lasting institutions of scientific education.
Faraday became a bookbinder’s apprentice in his teens and continued his education by reading the books he was binding. An article on electricity in the Encyclopedia Britannica inspired him to buy some equipment and conduct experiments himself.
Faraday joined London’s City Philosophical Society in 1810 to hear the lectures there and participate in scientific discussions. Then, in 1812, a client of the bookbindery gave the earnest young man tickets to hear a series of lectures by pioneering chemist Humphry Davy at the Royal Institution.
Thirsty for knowledge, Faraday took copious notes. He organized them, added illustrations and bound them into a book. Faraday secured an interview with Davy, presented him with the bound copy and asked to be hired as a lab assistant.
Davy was impressed but had nothing open at the moment. True to his word, however, he did hire Faraday the next year … at about $10 a week (the rough equivalent of $140 in today’s money).
A few years later, Davy asked his assistant to follow up on the work of Danish scientist Hans Christian Oersted, who had just discovered that an electrical current would deflect the needle of a magnetic compass. Faraday theorized that magnets created force fields, and he designed an experiment that significantly one-upped Oersted in 1821.
Faraday suspended a wire above a magnet. When he passed a current through the wire (whose bottom end hung in a dish of conductive mercury), the wire rotated around the magnet, following lines of magnetic force. It was a prototype for the electric motor, using electricity to create motion. It just needed to be scaled up.
The discovery was a sensation — perhaps a little too much of one. Davy, a scientific rock star of his day, was envious. He accused Faraday of stealing the idea from him and tried to block the young man’s election to the Royal Society. Davy backed off but never withdrew the charges. Faraday became a Fellow of the Royal Society and lab director at the Royal Institution in 1825.
Faraday decided to tread gingerly and shied away from electrical experimentation. He worked instead on analytical chemistry and the compression of gases, discovering benzene in 1825.
Davy died in 1829, perhaps from the after-effects of his frequent inhalation of nitrous oxide and other gases, including carbon monoxide. That gave Faraday free rein to resume his work on electricity.
He discovered electromagnetic induction in 1831. Reversing his effect of using a magnet and electricity to create motion, he used a magnet and motion to generate electricity. No messy, voltaic cells needed, it was the progenitor of steam, hydro and diesel generators.
Faraday plumbed the mysteries of electrochemistry in the 1830s, coining such words as electrode and ion, and establishing the laws of electrolysis.
But wait, there’s more.
In 1845, he suspended a heavy piece of glass between the poles of an electromagnet, watching the glass twist into alignment with the magnetic field. Other materials produced the same result, which Faraday named diamagnetism, the propensity of a nonmagnetic substance to create an opposing field in the presence of externally applied magnetism.
He also discovered the magneto-optical effect, also called the Faraday effect, that very same year: A magnetic field can rotate polarized light.
All this work — integrating magnetism, electricity, chemistry and light — eventuated in Faraday firmly establishing the field theory of electromagnetism, a foundation of modern physics.
Remembering his own education through public lectures, Faraday founded the Royal Institution’s Christmas Lectures on scientific topics. They’ve gone on since 1825, interrupted only during World War II. They’ve been on television since 1966 and are now supplemented by interactive online features.
Faraday also served as a science adviser to British governments for more than three decades. He worked fervently for the electrification of lighthouses.
Faraday died in 1867. His name is honored in the scientific world not only by the Faraday effect and the Faraday cage apparatus, but by two electrical units of measure and a physical constant. The farad is the humongous unit of capacitance, equal to one coulomb per volt. Because the unit is so huge, you usually see capacitance measured in micro-, nano- or picofarads.
The faraday is a unit of electric charge that can electrolytically deposit one mole of an element or univalent ion. It’s equal to Avogadro’s number multiplied by the charge of a single electron, or approximately 96.4853 kilocoulombs or 26.8015 ampere hours, and is also known as Faraday’s constant.
Source: Royal Institution, others
Photo: Michael Faraday was in many respects the Einstein of 19th-century physics. Faraday’s midcareer breakthroughs of the 1820s through ’40s were closer in time to Einstein’s revolutionary 1905 papers than those papers are to now.
Image from Millikan and Gale’s Practical Physics (1922)
This article first appeared on Wired.com Sept. 22, 2008.
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