Helium doesn't change the pitch of your voice? It really only changes the timbre. The speed of sound is three times faster in helium than in normal atmospheric air - faster speed means increased resonant frequencies, which means "higher" timbre. It does the same thing in wind instruments!
Carbon hexafluoride lowers the timbre of your voice? Just like helium, (except the opposite) the speed of sound is changed - this time decreasing the resonant frequency.
At normal pressures, helium will remain a liquid at absolute zero.
Helium is most commonly used in hospitals. (To supercool magnets in MRI machines.)
Of all the elements, helium has:
- The highest work function
- The highest heat conductivity (at the lambda point)
- The lowest boiling point, and
- Near-infinitely small flow viscosity below 2.17K (the lambda point).
- The most harmless element
- The most surprising element
- A gas the longest (gets the coldest), and is
- A very picky element (no holy containers - not even if you buy them in Jerusalem).
Helium atoms have a higher average velocity than the earth's escape velocity.
Since January 2008, helium producers worldwide have raised their bulk prices by 50%.
Currently there is a helium shortage in the world.
Helium is the second most abundant element in the universe.
The U.S. produces 90% of the world's helium.
What does all this mean?
1) Nick has been working on his liquid helium research too much, and
For more interesting and somewhat amusing anecdotes concerning liquid helium and my other noble gas adventures, stay tuned. For now, the liquid helium research is SECRET... so that the terrorists don't find out...