in the Earth's
SURFACE.
The Big Bang Theory Season 7, Episode 3
...with silicone RTV
to provide a better mounting SURFACE?
The Big Bang Theory Season 2, Episode 18
...on a SURFACE located
at the farthest reaches of our cosmos.
The Big Bang Theory Season 6, Episode 5
If there is life beneath
the SURFACE of these planets,
The Big Bang Theory Season 11, Episode 10
that's just a doodle of
a hyperelliptic Riemann SURFACE.
The Big Bang Theory Season 7, Episode 20