Question: Which group of scientists do you think made the biggest advance?

Laurence Perreault Levasseur answered on 24 Jun 2014:

Pretty clever, joshua904 😉

Ok so… I think one of the most important leaps of how we understand nature has been the whole journey of how atoms, and then quantum mechanics and quantum field theory were discovered. I say this because it’s a MAJOR departure from the philosophy of what science and even the universe was supposed to be and do and work.

Before that, every single scientist (I think, but I wasn’t around at the time…) would have said that the world is deterministic. That is, if I know precisely enough the initial conditions and I have the right mathematical model of nature, I can predict the outcome of any experiment with infinite precision. They would also have said, probably, that it’s possible to change the energy of things like atoms or light in a continuous way. That what ever the amount of energy, I can give it to an electron orbiting an atom (well, they didn’t really know about electrons or atoms, but that’s the idea), the worse thing that will happen is that the electron will be kicked out of its orbit.

The discovery the atom and of quantum mechanics was a complete revolution of that whole deterministic philosophy which had dominated scientists’ view for millennia! Scientists had to accept that outcome of experiments are intrinsically probabilistic, not because they don’t measure things precisely enough, but because of fundamental uncertainty principles in nature (like the fact that you can’t know both the momentum and the position of a particle at the same time, so you can’t predict where it’ll be!! If you know how fast it’s going, you don’t know where it is, and if you know where it is, you have no clue how fast it’s going – because it’s IMPOSSIBLE to know!!! ). They had to accept that particles sometimes look like waves, sometimes like particles. It’s really counterintuitive, but that’s how nature works.

I’d say it’s the biggest advance because of that fundamental philosophical shift. That was such a big shift that even Einstein (who is really one of the main protagonists who started that revolution) wasn’t able to accept it, and he fought it all his life. All his life he refused to accept quantum mechanics and searched for an alternative theory (and he failed). In my opinion that really marks the beginning of modern physics, chemistry and biology.

Quantum mechanics also made possible HUGE technological revolutions. Because of quantum mechanics, we have semi-conductors, which means things like computers, internet, smartphones, all those things that we seemingly can’t live without.

For the historical characters that were part of this great story, you can took at this really good series of documentaries:
http://topdocumentaryfilms.com/atom-tim/

Or, you can also ask me another question 😉

Edit:
This documentary also does a very good job at explaining quantum mechanics
(part 2 of 2 of a series, part 1 is about ‘everything’ – or the whole Universe)