The Hamburger Postulate

"The Hamburger Postulate" is the fifth episode of the first season of the  sitcom The Big Bang Theory. This episode first aired on October 15, 2007.

Summary
Leslie Winkle seduces Leonard, but only wants a. Leonard is fixated on what Penny thinks of his actions.

Extended Plot
Leonard and Sheldon are beating Raj and Howard when they recreated the (with major nerdy alterations). Penny comes to take their order, when they bump into Leslie Winkle. She tells Leonard that the Physics Department Orchestra needed a. Leonard agrees to join seeing as he plays the cello. Penny asks whether there was anything going on between Leslie and Leonard. Leonard tried to deny it, but Sheldon abruptly said "He asked her out once, it was an embarrassing failure". Penny mentioned they would have made a cute couple.

When the Physics Department Orchestra was rehearsing Leslie hinted sexually towards Leonard by saying "I admire your fingering, maybe next time you can try that on my instrument" and after that when, Leonard and Leslie were practicing alone, she said she was sexually available. After a brief conversation about Penny and "musical foreplay" Leonard and Leslie rushed to his room and initiated. A distressed Sheldon calls Penny to his apartment to interpret a "tie on the doorknob". Penny explains to him that the tie meant the people in the room didn't want to be disturbed because they are "getting busy", Sheldon told Penny that other than Leonard, Leslie was probably behind the door; this fact was confirmed moments later when they heard Leslie say (in a completely deadpan tone) "Oh, Leonard, you magnificent beast." Penny says "Good for them" in a doubtful tone.

The following morning, Sheldon wakes up to a terrible surprise; the equations on his white board had been tampered with. Although it solved the problem he had, he was still infuriated. Shortly after that, Leslie admits that she had corrected his equations. Later, Leonard bumps into Penny who asked him how was it sexual intercourse last night, which made Leonard ponder whether he wanted Penny or Leslie, though he settled for Leslie as she is currently making him happy.

Then, he tried to make his moments with Leslie more intimate, but Leslie revealed that the sexual intercourse had no emotional ties, leaving Leonard a little heartbroken. At the final scene, Sheldon explains his interest for the The Cheesecake Factory's hamburger (Title Reference), Penny comes along and asks how Leonard is doing with Leslie, after he explains the situation Penny says "...I'm sure there is someone out there who is just right for you" and walks away from them with a hidden smile. Leonard wonders if what Penny said "means anything".

Critics

 * "A very enjoyable episode of comedy and character development. It’s always difficult to put a new spin on sex jokes because we have seen a million of them. But Leslie’s dead pan science seduction is funny and Leonard’s character comes out looking sweet. Good job." - The TV Critic's Review
 * IMDb user reviews.

Costume Notes
Sheldon wears three t-shirts this episode. The first is the Batman Action Duo shirt, featuring Robin. While Leonard and Leslie are getting busy, he's wearing another Goodnight celestial graphic shirt (this time black and green instead of orange on dark gray). For the final scene at the Cheesecake Factory, he's wearing the rare Captain QO t-shirt.

Leonard wears a green t-shirt with a black star edged in red, a black t-shirt featuring the caffeine molecule, a blue shirt with an angular design, and a red shirt with a shard graphic.

Howard wears a green backed alien head pin, his Superman belt buckle, and still his red and black Vans. Playing Jinga and dancing to Latin music, he can be seen with a Coke bottle belt buckle.

Trivial

 * First time Penny serves them at the Cheesecake Factory.
 * Sheldon says, ". The study of signs and, it’s a branch of related to ." Interestingly, Sheldon's favorite character whom he tries to emulate, Spock, led his year in Semiotics, among other disciplines, at , according to Marvel-Paramount Comics Star Trek Early Voyages #1: Flesh of My Flesh.
 * Sheldons former favorite Burger was the one from Big Boy. From his point of view the Cheeseckake Factory Barbecue Burger surpasses the Big Boy because of it's "much more satisfying meat to bun to condiment ratio". He even want's to declare it as the new Tuesday hamburger and tries to permanently reserve the table for every Tuesday night.
 * Leonard Hofstadter states, " are magic, Superman is vulnerable to magic...", Superman's powers are derived from the yellow sun of Earth; they have no magical component, leaving the "Man of Steel" open to malignant sorcery (Superman: The Ultimate Guide to the Man of Steel, Superman vs. Magic). On the other hand, Superman similarly battles an ogre in Justice League of America Vol. 1 #49 (November 1966) with no ill effect.
 * Leslie Winkle points out that she saw Leonard's pupils dilate, which "unless [he's] a addict, points to sexual attraction". Heroin however is an, and opiates cause pupils to constrict, not dilate.  however (,  etc.) do cause pupils to dilate. To put it simply, Leslie's terminology is incorrect.
 * Johnny Galecki (Leonard) knows how to play the in real life.
 * Sheldon went to at the age of 11.
 * This time is one of the rare occurrences where Sheldon does not knock 3 times then says the name of the person he is trying to get a hold of.

Quotes

 *  Penny: Leonard, I didn't know you played the .
 *  Leonard: Yeah, my parents felt that naming me Leonard and putting me in advanced placement classes wasn't getting me beaten up enough.


 *  Sheldon: I like the hamburgers where we usually have hamburgers; you can’t make the assumption that I’ll like the hamburgers here.
 *  Leonard: I’m sorry. Give him a hamburger.
 *  Penny: Uh, which one, the Classic Burger, the Ranch House Burger, the Barbecue Burger or the Kobe Burger?
 *  Sheldon: Can’t we just go to Big Boy? They only have one burger. The Big Boy.
 *  Penny: The Barbecue Burger is like the Big Boy.
 *  Sheldon: Excuse me, in a world that already includes the Big Boy, why would I settle for something like  a Big Boy?
 *  Penny: Because you are not at Big Boy!
 *  Sheldon: Fine, I’ll have the Barbecue Burger.


 *  Penny: Gee, Sheldon, you’re asking the wrong girl. I’m usually on the other side of the tie.


 * Sheldon: Hold on, h-hold on! (clearly peeved)
 * Leslie: What?
 * Sheldon: Who told you, you could touch my board?!
 * Leslie: No-one.
 * Sheldon: I don't go into your house and touch your board!
 * Leslie: There are no incorrect equations on my board. (Leonard grins, Sheldon is furious)
 * Sheldon: Oh, that is so... so...
 * Leslie: I'm sorry, I gotta run. If you come up with an adjective, text me. (exits)
 * Sheldon: Inconsiderate. That is the adjective. Inconsiderate.


 * Howard: If you're into music, I happen to be a human beatbox.


 * Penny: Really?


 * Howard: (Beatboxing)


 * Penny: I'm actually not that into music.


 * Sheldon: My equations! Someone's tampered with my equations!
 * Leonard: Are you sure?
 * Sheldon: Of course I'm sure! Look at the beta function of quantum chromodynamics! The sign's been changed!
 * Leonard: Oh, yeah...but doesn't that fix the problem you've been having?
 * Sheldon: Are you insane? Are you of your mind? Are you- hey, look, that fixed the problem I've been having!
 * Leslie: (enters) You're welcome.
 * Sheldon: You did this?
 * Leslie: Yeah. I noticed it after I got up to get a glass of water, so I fixed it so now you can show that quarks are asymptotically free in high energies. Pretty cool, huh?
 * Sheldon: Cool?!