
"Helium."
The Big Bang Theory Season 2, Episode 5

Hey, in your super-cooled
HELIUM experiments,
The Big Bang Theory Season 9, Episode 16

You see, instead of
using liquid HELIUM...
The Big Bang Theory Season 11, Episode 8

I'm not seeing anyone
using liquid HELIUM vortices like this.
The Big Bang Theory Season 9, Episode 16