That’s a really nice question!
I’d have to say one of my lecturers from my undergraduate, Alex Hopkins. He was a very enthusiastic teacher of chemistry, funny and a nice guy. The fact I remember him shows he made an impact.
If I had to name a famous scientist though… possibly James Clerk-Maxwell. He made great advances in physics to unify the theories of electricity and magnetism, he made the first colour photograph, made improvements to steam engines, was an excellent mathematician and revolutionised the teaching of science in the UK, not just physics, when he was the first professor of experimental physics in Cambridge.
Like Michael, there are two that stick out for me, one living and one long-dead. We had a great lecutrer on evolution when I was at university called Mark Ridley (not Matt Ridley). He had a very deep understanding of the material he was teaching us but was not lost in the specifics of his own knowledge but was able to communicate it to any level of understanding. I still use the textbook he wrote for the course he was teaching us regularly.
And for my historical choice, Charles Darwin. There were lots of things about Darwin as a scientist that were infuriating to his colleagues and friends at the time he was alive. He was slow, a hyperchondriac and very reluctant to go out and publish his work. However, he was a model of thoroughness, meaning that he would collect lots and lots on evidence on a quesiton before he was confident enough of his answer to say “this is a scientific result”.
Currently, I’m really impressed by Brian Cox. A lot of scientists are a bit down on him – probably because he makes these snazzy programmes going to glamorous places all the time, and they think he skips lots of the science involved. But he’s a very good communicator and us scientists often forget that his programmes are aimed at people you aren’t particle physicists or astronomers. When I talk to my non-scientist friends, they get a lot out the programmes.
Patrick Moore was also very inspiring when I was starting to look at the sky, and meeting Bernard Lovell at Jodrell and hearing him discuss the early days of radio astronomy and getting this telescope built was also memorable.
I think my hero must be J J Thomson, first he postulated the existence of the electron, and then he discovered it and weighed it, using a magnetic field. I so doing he also invented the mass spectrometer which is what I use to measure the amount of drug that is present in blood samples. After that may be my boss, he has so much enthusiasm. We spend a lot to time discussing results and what they mean. Sometimes he is right and sometimes I am.