Michael Faraday
Michael Faraday | |
|---|---|
| Born | 22 September 1791 Newington Butts, Surrey, England |
| Died | 25 August 1867 (aged 75) Hampton Court, Middlesex, England |
| Nationality | British |
| Known for | Electromagnetic induction, lines of force, laws of electrolysis, the Faraday effect, diamagnetism |
| Scientific career | |
| Fields | Chemistry, Electricity, Magnetism |
| Institutions | Royal Institution |
Michael Faraday (22 September 1791 – 25 August 1867) was an English experimentalist whose discoveries founded the practical science of electricity and whose idea of lines of force filling the space around magnets and charges became, after Maxwell gave it mathematical form, the field concept of modern physics.
Faraday came to science without a university education. Apprenticed to a bookbinder, he was taken on at the Royal Institution as Humphry Davy's laboratory assistant in 1813 and remained there for the rest of his working life. In 1821 he produced the first continuous electromagnetic rotation — a wire circling a magnetic pole — the ancestor of every electric motor. On 29 August 1831 he demonstrated electromagnetic induction: a changing current in one coil wound on an iron ring induced a transient current in a second coil, with no contact between them. Within months he had built the homopolar or "Faraday disc" generator, in which a copper disc spun between the poles of a magnet delivers a steady current. In 1833–34 he established the laws of electrolysis, showing that the mass deposited at an electrode is proportional to the quantity of charge passed — the first strong quantitative evidence for a natural unit of electricity. In 1845 he found that a magnetic field along the path of light rotates its plane of polarisation (the Faraday effect), the first demonstrated link between light and magnetism, and in the same year identified diamagnetism. His experimental notebooks were published as Experimental Researches in Electricity (1839–1855), written almost entirely without equations.
Faraday declined a knighthood and twice refused the presidency of the Royal Society.
Lines of force and the road not taken
Faraday did not think of electric and magnetic action as instantaneous pull between distant bodies. He thought the space between them was in a state — strained, structured, carrying the action across at finite speed — and he took the curved iron-filing patterns around a magnet as a picture of that state rather than as a bookkeeping device. In his 1846 speculation "Thoughts on Ray-vibrations" he went further and suggested that light might be a vibration of the lines of force themselves, dispensing with a separate luminiferous medium.
Maxwell built his electromagnetic theory explicitly on this, beginning with "On Faraday's Lines of Force" (1855–56). But in the mathematisation the mechanical picture progressively dropped away, and by the twentieth century the field had become a mathematical object defined by its equations rather than a state of a medium.
On this wiki
That divergence is why Faraday is invoked so persistently by researchers catalogued here. The common argument is that Faraday's lines were a physical structure, that Maxwell retained the structure in the vortex-cell model of 1861–62, and that the later abandonment of the model — not the equations — was the mistake.
- Ionel Dinu, in "What's Behind Faraday's Magnetic Lines of Force?" (Electric Spacecraft Journal, 2006), argues directly that the accepted picture of lines of force as geometrical lines in empty space is inadequate, and proposes an interpretation that "restores the material aether as the seat of magnetic phenomena."
- "An Interpretation of Faraday's Lines of Force" treats a single line of force as a double helix of sinks and sources closed on itself into a toroidal ring vortex — connecting Faraday to the toroidal ring models collected under Category:Vortex Theory.
- Edward M Kelly, "The Mechanics of Faraday's Law in the Vortex Sponge" (Galilean Electrodynamics, 1998), works out induction in an explicitly mechanical medium.
- David Tombe, "The Faraday Paradox and Newton's Rotating Bucket" (2008), ties the rotating-magnet paradox to inertia and to the angular velocity of the aether, joining Faraday's problem to Mach's rotating-bucket question.
A second and largely independent thread concerns the Faraday disc and unipolar induction, where the question of whether the magnetic field rotates with its magnet remains experimentally contested: Jorge A Guala-Valverde and Pedro Mazzoni, "The Unipolar Faraday Generator Revisited" (1993); Domina Eberle Spencer and Philip J Mann, "Electromagnetic Postulates and Unipolar Induction" (2009); Bruce E DePalma, "Notes on the Faraday Disc: A Collection of Essays" (1995); and Thomas F Valone, "The Homopolar Handbook: A Definitive Guide to Faraday Disk & N-Machine Technologies" (1994), which carries the same device into the new energy literature.
A third thread disputes the standard statement of Faraday's law itself. Stewart Ian Wells argues in "Dual Dilemma From Faradays' Law – Constructive Fraud at the Foundation of Electrodynamics" (2008) and "Faraday Pressure and Energy Conservation" (2009) that the flux rule conceals an energy-accounting problem; Ivor Catt raises a superposition objection in "Does Faraday Allow Superposition?" (2011); and Ray T Smith tests the Weber-Ritz and Faraday-Maxwell formulae against each other experimentally in "Weber-Ritz & Faraday-Maxwell Formulae: Induction Experiment Test" (Galilean Electrodynamics, 2001).
It should be said plainly that the flux rule is not in doubt as a working relation — it is verified continuously by every transformer and generator. What is at issue on this wiki is what the field is, and whether Faraday's own answer was abandoned prematurely.