Michael Faraday is regarded as one of the greatest experimental scientists of all time. Even Albert Einstein (1879—1955) considered him to be one of the most important influences in the history of physical science. Yet the man whose discoveries and inventions, amongst them the electric motor, electric generator and the transformer, were to have such a profound impact on modern life, might not have entered the scientific arena at all but for certain fortuitous events in his youth. The first was his apprenticeship at a bookbinder’s when he was thirteen. Here his interest in science and in particular electricity was stimulated upon reading pages from the books he was tasked to bind. The second fortunate incident was his appointment as assistant to the renowned chemist Sir Humphrey Davy (1778—1829), who had remembered the young Faraday attending his lectures. The temporary post soon turned permanent and shortly afterwards Davy took Faraday with him on a grand European tour which gave the young man the rare opportunity to meet and learn from many of the leading physicists and chemists of the day. Much of Faraday’s early work as a scientist in the 1 820s was not in physics, the area which ultimately led to his breakthrough inventions, but in chemistry. In 1823, he became the first person to liquify chlorine, albeit accidentally, while he was conducting another experiment. He quickly deduced how the new form of chlorine had been obtained and applied the process, which made use of pressure and cooling, to other gases. By employing his talent as an outstanding analyst of his own chemical experiments, he also went on to discover benzene in 1825.
THE ELECTRIC MOTOR
Yet it is physical science, in particular his work involving electricity, for which Faraday is best remembered today. As early as 1821, he was able to create the first electric motor after discovering electromagnetic rotation. He had developed Hans Christian Oersted’s (1777—1851) 1820 discovery that electric current could deflect a magnetic compass needle. Faraday’s experiment proved that a wire carrying an electric current would rotate around a fixed magnet and that conversely, the magnet would revolve around the wire if the experiment were reversed. From this work, Faraday became convinced that electricity could be produced by some kind of magnetic movement alone but it took ten further years before he successfully proved his hypothesis. In 1831, by rotating a copper disk between the poles of a magnet, Faraday was able to produce a steady electric current. This discovery allowed him to go on to produce electrical generators, the transformer (also invented independently at around the same time by an American, Joseph Henry) and even the dynamo: inventions which can truly be claimed to have changed the world!
The reason Faraday was able to make such advances was because from early in his career he had rejected the concept of electricity as a ‘fluid’, an idea that had been accepted up until that time, and instead visualised its ‘fields’ with lines of force at their edges. He believed that magnetism was also induced by fields of force and that it could interrelate with electricity because the respective fields cut across each other. Proving this to be true by producing an electric current via magnetism, Faraday had discovered electromagnetic induction. He was encouraged by this and went on to explore the idea that all natural forces were somehow ‘united’. He then focused on how light and gravity were related to electromagnetism. This led to the discovery of the ‘Faraday effect’ in 1845 which proved that polarised light could be affected by a magnet. James Clerk Maxwell proved that light was indeed a form of electromagnetic radiation, and eventually provided the mathematical expression for Faraday’s law of induction.
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