Asked to name a great physicist, most people would mention Newton or Einstein, Feynman or Hawking. But ask a physicist and there's no doubt that James Clerk Maxwell will be near the top of the list. Maxwell, an unassuming Victorian Scotsman, explained how we perceive colour. He uncovered the way gases behave. And, most significantly, he transformed the way physics was undertaken in his explanation of the interaction of electricity and magnetism, revealing the nature of light