the abbreviation for HELIUM.
The Big Bang Theory Season 7, Episode 3
You and Sheldon already came up
with your superfluid HELIUM model.
The Big Bang Theory Season 9, Episode 16
One time my brothers
made me breathe HELIUM.
The Big Bang Theory Season 12, Episode 6
"Helium."
The Big Bang Theory Season 2, Episode 5
I'm not seeing anyone
using liquid HELIUM vortices like this.
The Big Bang Theory Season 9, Episode 16