You see, instead of
using LIQUID helium...
The Big Bang Theory Season 11, Episode 8
The correct answer is, "When covered by
LIQUID sufficient to reduce the coefficient...
The Big Bang Theory Season 2, Episode 5
The world's most boring LIQUID
and the world's most boring vegetable,
The Big Bang Theory Season 10, Episode 13
Floating in a warm pool
of LIQUID
The Big Bang Theory Season 12, Episode 19
They make up a non-Newtonian fluid
which is LIQUID...
The Big Bang Theory Season 2, Episode 3