#4 – Michael Faraday

One day sir, you may tax it.
- Michael Faraday, asked by the British Minister of Finance about the practical value of electricity

With Michael Faraday we begin to reach the most rarified heights of physics achievement. Faraday worked largely in the first half of the 19th century when the lines between physics and the other sciences were not as clearly drawn. Faraday blazed a trail of glory through the rapidly developing sciences of physics and chemistry.

In his early years as a scientist he built the first primitive electric motor, discovered electromagnetic induction, and mutual induction, formalized the concept with Faraday’s law, and invented the dynamo.

He pioneered the concept of lines of force and was able to develop them in such a way as to classify their interaction with materials. This was used to show how conducting materials can be used to shield objects from electric fields. Today we call these kinds of devices Faraday cages in his honor. Before Faraday the connection between electric and magnetic fields was not well understood and indeed it remained to Maxwell to finish the mathematical connection. But Faraday saw that there was a connection and he made much of the progress in connecting the previously fragmented and badly understood science of electricity and magnetism. In fact, you can make the case that he was the first to connect electromagnetism and light with his experiments with magnetic fields and polarization filters.

As a chemist he developed electrolysis and methods for liquefying gas. From a theoretical perspective he came up with the idea of oxidation numbers. If I may quote Wikipedia, he also worked on what would become nanotechnology more than a century later: “Faraday was the first to report what later came to be called metallic nanoparticles. In 1847 he discovered that the optical properties of gold colloids differed from those of the corresponding bulk metal. This was probably the first reported observation of the effects of quantum size, and might be considered to be the birth of nanoscience.”

In some ways he was the Feynman of his day. Really it might be more accurate to say Feynman was the Faraday of his day. Faraday gave a popular series of lectures to the public, and wrote a lovely popular explanation of the chemistry and physics of a candle flame, called The Chemical History of a Candle. He participated in early environmentalism and investigated water and air pollution. Even Feynman’s Challenger accident has a bit of a parallel in Faraday, who used his intellect in the investigation of an explosion in a coal mine.

You could argue that he was the greatest experimentalist of all time. I would agree with you.

The list so far (click the category name for links):
4. Faraday
5. Feynman
6. Rutherford
7. Schrodinger
8. Dirac
9. Thomson
10. Pauli

The three remaining are probably something roughly approaching obvious, but you can at least be kept in suspense by their ordering!