Goddamn. How can you not love Minute Physics? This week, Henry Reich explains a family of particles that are the talk of the physics world: neutrinos!
Neutrinos have been in the news a lot lately. Remember that experiment at CERN where scientists claimed to observe particles travelling faster than light? Those were neutrinos. But since the result of that study has yet to be confirmed, Reich focuses his video on what we're sure we know about this family of leptons.
Here's a little background to help you get into the video: The neutrino was first theorised in 1932 by Wolfgang Pauli. Scientists had added up the mass and charge on either side of equations describing nuclear decay and found that they came out equal. But new developments in quantum mechanics suggested that particles in atomic decay also had a property they called spin—kind of like a planet rotating on its axis. When Pauli took this new development into account, his equations didn't add up. Spin wasn't conserved, therefore energy wasn't either. WTF? Pauli's conclusion: that another type of particle must be a product of nuclear decay, accounting for this difference in spin...Neutrinos! (Actually, he called them neutrons first, but someone else had already claimed that name so it was changed to neutrino.)
The video focuses less on history and more on creative solutions experimental physicists have to come up with to detect neutrinos—like using the entire continent of Antartica to detect them. Watch it. Get smart. [Minute Physics]