The Big Bran Hypothesis

"The Big Bran Hypothesis"
The Big Bang Theory episode
Episode no.	Season 1 Episode 2
Directed by	Mark Cendrowski
Written by	Robert Cohen & David Goetsch (teleplay) Chuck Lorre & Bill Prady (story)
Production code	102
Original air date	October 1, 2007

"The Big Bran Hypothesis" is the second episode of the American sitcom The Big Bang Theory originally aired on CBS in the United States on October 1, 2007. Written by Robert Cohen and David Goetsch and directed by Mark Cendrowski.

Plot

Penny interrupts the boys sharing Thai takeout and having a Superman movie marathon. She asks Leonard to sign for a package while she is out the next day and Leonard agrees, hoping to impress her.

While Penny is sleeping, Sheldon breaks into her apartment, obsessed over her uncleanliness, and begins to clean. A sleepy, frustrated Leonard comes across the scene (with a glowing lightsaber), tries to stop him, but ends up helping him clean anyway. They decide to speak in an exaggeratedly low register because, as Sheldon points out, evolution has allowed for women to be sensitive to high pitch noises while they sleep so they can be roused by the noise of a crying infant; this proves to be true when the nervous high-pitch tones of Leonard's voice cause Penny to toss and turn in her sleep.