JAMES CLERK WHO?
When teaching engineering, I would at some point attempt to extol the great achievements of this small country of ours. Alas, most of the great Scots I named were greeted with a total lack of recognition, and a look of, “what’s he on about and why is he wasting our time”, and it was only when I began to mention recent sporting stars that a connection was once again made. So, I tried another approach. “Have you heard of Einstein then?” “Yes”, they all responded. At last, there was recognition of someone who had a connection to what they were doing. “Do you know then that Einstein had, in his study at Princeton University, a picture of a Scottish physicist on his wall?” Blank looks. “His name was James Clerk Maxwell and he was born about 20 miles from where this class is taking place." I always felt it a little bit sad that this was the outcome every time I tried to inject, not only pride in Scotland, but a sense of belief in what the students sitting in front of me could aspire to.
A modicum of interest was all I needed to proceed with my tail of James Clerk Maxwell and so I begin. Maxwell was born in Edinburgh in 1831, the son of a Scottish advocate and went on to be educated at Edinburgh Academy followed by Edinburgh University and finally Cambridge University. His greatest achievement was his theory of electromagnetic radiation published in 1865 and entitled, ‘A Dynamical Theory of the Electromagnetic Field’, which demonstrated that electricity, magnetism and light were all the same phenomena; that is that electrical currents and electrical charge produces electrical and magnetic fields which travel through space at the speed of light. From this theory, and his accompanying wave equations, he was able to make a very accurate prediction for the speed of light and also postulate the possibility of radio waves. One person who recognised Maxwell’s contribution to science was Albert Einstein, who famously said on a visit to Cambridge in the 1920’s that it was not so much Newton that he succeeded but instead Maxwell, saying that he ‘stood on the shoulders of Maxwell.’ Another major contribution to the modern world by Maxwell, was the first colour photograph, taken in 1861 - see above.
At the heart of Maxwell’s work on electromagnetic radiation are four differential equations (see below - Maxwell’s original paper had 20 equations) which describes the production and relationship between electrical and magnetic waves.
The first equation (Gauss’s Law) describes the relationship between a static electric field and the electric charge that produced the field. The second equation (Gauss’s Magnetic Law) states that there are no magnetic quantities analogous to electric charge (no monopoles). Instead magnetic field lines form complete loops or dipoles. The third equation (Faraday’s Law) describes how a time varying magnetic field can produce an electric field. The Forth equation ( Ampere’s Law) states that a magnetic field can be produced by an electrical current or an electric field.
Another of Maxwell’s great achievement was in understanding how different colours can be produced by combining different quantities of red, blue and green. He would demonstrate the principle with a three-segment colour wheel - one segment for blue, one for green and one for red – and by spinning the wheel another new colour would be produced. It was an extension of this work on his three-colour principle that led to his invention of colour photography and it is a principle that continues to this day.
So, was Einstein right about Maxwell’s place in scientific history? Most certainly he was, for the work done by this Scotsman provided the world with the foundation for its communications, such as mobile telephones and the internet, as well as our ever-bigger colour televisions and computer screens. Truly a scientific giant!
Maxwell died in 1879 in Cambridge and is buried in Parton in Kirkcudbrightshire in the south-west of Scotland.
And what of the class? I suppose the best I could hope for was that at least his name was now known and that a few more people had a rough idea of his impact on our world today. It was important that they also knew of the brilliance of this nation of ours (Maxwell was one of many I would mention in this way) and that they should be more confident in their own abilities because it is too often the case that we, as Scots, are not that confident (an observation from working with College students for more than 28 years) and that, from a political standpoint, we are often told that we are not capable of running our own country; what rubbish!
1. Gauss Law for static electric fields.
2. Gauss Law for static magnetic fields.
3. Faraday Law states changing a magnetic field will produce an electric field.
4. Ampere’s states changing an electric field will produce a changing magnetic field.
Crossword No. 1 Solutions.
Across: 1. avarice. 5. anger. 8. twenty-two. 9. Let. 10. dwang. 12. roadman 13. international.
15. station. 17. Poreč. 19. ape. 20. overturns. 22. tides. 23. tedious.
Down: 1. acted. 2. ace. 3. integer. 4. entertainment. 5. aroma. 6. gold miner. 7. retinal.
11. attracted. 13. instant. 14. imputed. 16. irons 18. cases.