Monday, February 11, 2008
Okay, you will not even believe what happened to me the other day. I saw He-4 superfluid creep. I know it is exciting. Anyway as you all know He - 4 is a boson which means multiple atoms can share the same energy states (unlike fermions, that can not share energy states because of their 1/2 integral spin). So anyway, when He-4 reaches 4 Kelvin (about -452.5 degrees Fahrenheit) all of the atoms drop to the same energy state, leaving a gap in the energy states. Because of that gap it become a superfluid which is a perfect conductor of heat. Not a good conductor but a perfect conductor. So it will start to climb up the walls of the dewar flask as it gains this weird surface tension, that is called the super fluid creep. I looks like a jar full of water, if fact it was hard to even see that. The actual viewing is incredibly anticlimactic but it is cool to know that I have seen something that less that 500 Americans have ever seen.