A Michael Faraday primer for COSMOS!

I’ve really been enjoying the new version of “Cosmos: A Spacetime Odyssey,” though this Sunday’s coming episode has me more excited than any other!  Titled “The Electric Boy,” the episode will focus on Michael Faraday (1791-1867), one of the most influential scientists of the 19th century and my personal hero.

So who was Michael Faraday?  He came upon the scientific scene at a time when physics was on the verge of a revolution that would unify the seemingly disparate forces of light, electricity and magnetism — and he played a pivotal role in unifying all of them!  He also made fundamental contributions to chemistry, and on top of it was an amazing teacher whose surviving Christmas lectures are insightful and enjoyable 150 years after their conception.

Portrait of Michael Faraday, 1842.  Via Wikipedia.

Portrait of Michael Faraday, 1842. Via Wikipedia.

All of Faraday’s achievements are even more remarkable considering his humble beginnings.  The son of a blacksmith, he was of a lower social station and beneath the upper class of people who traditionally became scientists.  He had little formal education; when, at the age of 14, he became the apprentice of a local bookbinder, he learned as much as he could from the books available.  Science, and electricity in particular, caught his attention, and he became determined to pursue a career.  Notably, he was greatly inspired by Jane Marcet‘s book Conversations in Chemistry, and he would become friends with her later in life.

At age 20, after leaving his apprenticeship, Faraday applied for a job, any job, in the Royal Society; he literally received no response.  Undeterred, he attended lectures by several famous scientists, including the chemist Humphry Davy. Faraday took extensive notes of Davy’ lectures, and sent them to the chemist as a job application of sorts.  Davy was impressed, and employed Faraday immediately.  However, Davy was planning a multi-year tour of the European continent, and the only way he could bring Faraday along was as his  personal valet!  It was a difficult journey for Faraday — Davy’s wife treated him like garbage — but he learned much from the experience and gained many important contacts.

In 1821, Faraday finally earned a prestigious position as the Assistant Superintendent of the House of the Royal Institution.  He soon made important discoveries in chemistry, including the discovery of benzene in 1825.  However, at about the same time he was taking on his role at the Royal Institution, a fateful experiment in electricity was performed in Denmark.  In 1820, Hans Christian Oersted discovered, and simultaneously demonstrated to an audience, that magnetism is produced by an electrical current.  This was not quite accidental, as Oersted was driven by a philosophical view that all the forces must arise from a single, fundamental force.  However, this was the first demonstration of such unification, and it had a profound influence on physics.  Around the same time, a number of scientists suggested that light could magnetize iron, seemingly showing an additional connection between electricity, magnetism and light; unification was soon on everyone’s minds. 

A watercolor painting of Faraday in his laboratory, by Harriet Jane Moore, via Wikipedia.

A watercolor painting of Faraday in his laboratory, by Harriet Jane Moore, via Wikipedia.

The greatest breakthrough came from Faraday.  He reasoned that, if electricity could produce magnetism, it must be possible for magnetism to produce electricity, as well.  In 1831, his intuition was proven correct, though not in the way he or anyone expected!  It turns out that a changing magnetic field will produce an electric field, or induce an electric current in a circular wire; this phenomenon is now known as Faraday induction.

faradayslaw

Illustration of Faraday’s law: a changing magnetic field induces a circulating electric field.

Faraday published his results in the Philosophical Transactions of the Royal Society to immediate acclaim, sparking a 29 part series of papers on electrical experiments, simply titled “Experimental Researches in Electricity.”  Nearly every one of these papers is a treasure, each filled with stunningly complete experimental observations.

One of the first of these was a detailed investigation of what might be called a “unified theory of electricity.”  In Faraday’s time, researchers were not entirely convinced that there was a single type of electricity, and tended to divide them into three classes: “common” (static, lightning), “voltaic” (from a battery), and “animal” (from animals like electric eels).  Each of these types of electricity seemed to have different properties, but Faraday made thorough studies to show that all three are in fact the same.

Speaking of animal electricity, in 1839 Faraday and his assistants studied the electrical properties of electric eels.  As reliable measurement devices didn’t exist back then, the researchers would test the eels’ electrical power by sticking their bare hands on them.

"Hi.  I'm an electric eel.  You really shouldn't be grabbing me barehanded."

“Hi. I’m an electric eel. You really shouldn’t be grabbing me barehanded.”

It is often said that physicists do their best work in their late 20s and early 30s, and not much of any importance after that.  Faraday demonstrates that this is nonsense: in 1845, at age 54, Faraday made two more monumental discoveries.  The first of these was diamagnetism, the ability of many materials to become “anti-magnetic” when exposed to a strong magnetic field.  It is now known that even living creatures are weakly diamagnetic, as was infamously shown in 2006 when a living frog was levitated in a magnetic field.

The second of Faraday’s discoveries pushed the unification of the fundamental physical forces even further!  He demonstrated that a light passing through a material in a magnetic field has its direction of polarization (oscillation) rotated, a phenomenon now known as Faraday rotation.  This was a strong indication that light and magnetism are related to one another and, in turn, that light and electricity must also be related.

Illustration of Faraday's rotation experiment.

Illustration of Faraday’s rotation experiment.

It is in the discovery of Faraday rotation that one can see, quantitatively, how thorough an experimenter Faraday was.  In order to prove the universal nature of the effect, he tested the rotation with no less than 150 different liquid samples!

The observation of Faraday rotation set the stage for the complete unification of electricity, magnetism and light, as was achieved theoretically by James Clerk Maxwell in 1861, when he published the first form of Maxwell’s equations and suggested, on the basis of these equations, that light is in fact an electromagnetic wave.  In a very real sense, this discovery marked the birth of modern physics and the quest to unify all of the seemingly different forces of nature, a quest still ongoing today.  And Faraday’s work was a principal inspiration for it all, as Maxwell himself admitted in A Treatise on Electricity and Magnetism:

If by anything I have here written I may assist any student in understanding Faraday’s modes of thought and expression, I shall regard it as the accomplishment of one of my principal aims — to communicate to others the same delight which I have found myself in reading Faraday’s Researches.

Faraday was not a mathematician, but he had an incredible intuition.  He even leapt ahead of many others in his time and, in 1851, attempted to find experimentally a connection between electricity and gravity.  No connection was found, but one of the major goals of modern string theory is to unify gravity to the other forces of nature.

There are so many more discoveries he made, and so many other aspects of his life to discuss, that a single blog post cannot contain them all!  I will simply mention a few other highlights of his life that I have come across in my blogging.

I have mentioned Faraday’s wonderful lectures.  For years, he ran a series of Christmas lectures on science at the Royal Institution, combining experimental demonstrations with theoretical insight.  Only two of these lectures were transcribed for posterity, but they are wonderful.  There is his The Chemical History of a Candle (1848), as well as his Forces of Matter (1859); both can be found online, and I am sorely tempted to try and perform one of them for a modern audience!

Faraday giving a Christmas lecture in 1856, via Wikipedia.

Faraday giving a Christmas lecture in 1856, via Wikipedia.

Faraday was also a man with a strong moral conscience.  He was devoutly religious, and his Christian faith seems to have boosted his desire for peace, justice, and kindness.  He performed much public service, including participating in an inquiry into a coal mine disaster.  He also showed environmental tendencies, famously writing a letter to The Times of London in 1855 complaining about the horrible pollution in the Thames.

Caricature of Faraday published in Punch in July 1855, via Wikipedia.

Caricature of Faraday published in Punch in July 1855, via Wikipedia.

Perhaps my favorite story about Faraday is the correspondence he had in 1844, at the height of his popularity.  In that year, a young woman wrote to him, asking if she could join him in his laboratory as an assistant.  Such a thing was almost entirely unheard of at the time.  Though Faraday did not take her on, he wrote as gracious a letter as could be imagined in response, an excerpt of which is below:

That with your deep devotion to your object you will attain it, I do not doubt.  Not that I think your aspirations will not grow with your increasing state of knowledge, and even faster than it; but you must be continually passing from the known to the unknown, and the brightness of that which will become known, as compared to the dulness, or rather obscurity, which now surrounds it, will be, and is worthy to be, your expected reward.  And, though I may not live to see you attain even what your mind now desires, yet it will be a continually recurring thought in my imaginings, that if you have life given you you will do so.

The woman in question was none other than Ada Lovelace, who has become famous in her own right for work in mathematics.

Ada Lovelace, 1840.  Via Wikipedia.

Ada Lovelace, 1840. Via Wikipedia.

Faraday was a brilliant, yet humble, scientist.  He was one of the most influential scientists of the 19th century, helping to usher in the modern era of physics, yet he came to this position against the odds, and with society predisposed against him.  For these, and many reasons, he is my scientific hero!  I’m looking forward to seeing what Cosmos has to say about him.

Michael Faraday, around 1861, via Wikipedia.

Michael Faraday, around 1861, via Wikipedia.

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7 Responses to A Michael Faraday primer for COSMOS!

  1. Excellent post, informative and well written. Thank you.

  2. Cranky Old Prof says:

    Very interesting post. One minor correction: Ada Lovelace did no original work in mathematics. In her own time, her fame derived mostly from being Lord Byron’s daughter. Her translation and notes to Luigi Menabrea’s French-language article about Babbage’s Analytical Engine (her only scientific publication) were mostly forgotten until rediscovered by Turing in the 1950s. It contains no significant mathematics (even the Bernoulli numbers used in them were computed by Babbage, as the letters between them show). It does contain some interesting speculations about the potential power of computing machinery like that Babbage was attempting to build at the time.

    • Thanks for the comment! I was specifically vague about Lovelace’s work, since lots of people argue about how big a contribution she made. As you said, she is known for her work on Babbage’s difference engine, which is best described as mathematical work, even if only translation and interpretation.

  3. Tommy says:

    Thank you for this informative primer!

  4. James Makay says:

    You have piqued my curiosity once again!

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