the abbreviation for HELIUM.
The Big Bang Theory Season 7, Episode 3
"Helium."
The Big Bang Theory Season 2, Episode 5
Forget HELIUM. The real superfluid
is the fruit punch in this mug.
The Big Bang Theory Season 9, Episode 16
You and Sheldon already came up
with your superfluid HELIUM model.
The Big Bang Theory Season 9, Episode 16
Helium has
an atomic number of two.
The Big Bang Theory Season 7, Episode 3