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"The Tangerine Factor" is the seventeenth and final episode of the first season of the American sitcom The Big Bang Theory. This episode first aired on Monday, May 19, 2008.


After a bad breakup, Penny finally agrees to go out on a date with Leonard, but the two of them both develop doubts and both turn to Sheldon, of all people, for advice. Sheldon believes Szechuan Palace is passing orange chicken as tangerine chicken.

Extended Plot[]

The Tangerine Factor 7

Howard trying to teach Mandarin to Sheldon.

We open to Howard helping Sheldon to learn Mandarin Chinese. Sheldon wants to confront Schezwan Palace about using oranges instead of tangerines in their tangerine chicken (oranges being much cheaper than tangerines). Leonard comments that he'd be more concerned about what they're using as chicken. Penny storms in; she needs to use their window - she opens it and throws an 80GB white iPod out, yelling "drop dead you self-centered bastard", subsequently explaining that Mike had written about their sex life on his blog. She storms out as Howard drops Sheldon's Chinese lesson because he has "a blog to find".

Leonard tries to talk to Penny who yells at him through the closed door; "go away!". Sheldon notes that her ire is understandable because emotional responses such as Penny is experiencing initiate in the older amygdala portion of the brain, while speech is centered in the much more recently developed neocortex. The former can easily overpower the latter, giving credence to the concept of being rendered speechless. (Sheldon may be familiar with Brain: The Complete Mind: How It Develops, How It Works, and How to Keep It Sharp by Michael Sweeney.) After a glare from Leonard, Sheldon offers that "maybe she just doesn't wanna talk."

Raj comes in, happy that he found an iPod. Howard notes that it's smashed beyond repair, and Raj notes that he can still sell it on eBay as "slightly used". Howard is frustrated that he can't find the blog about Penny's sex life. Leonard wants to help Penny. Howard suggests that he hold her, comfort her, and if he thinks it's a good time, to try to cop a feel, noting "be sure to sit on your hands a bit so they're warm". Sheldon doesn't believe that there is any social_convention|social convention that requires Leonard to be involved in the matter at all. Leonard points to chivalry. Sheldon doesn't think that the 12th century Code of Chivalry applies in these circumstances (and Leonard would have to be knighted for it to apply). (The complete code can be found within Maxims of Christian Chivalry by Kenelm Digby.)

The Tangerine Factor 6 Penny and Leonard view a computer

Leonard reading about Penny's love life on ex-boyfriend's blog.

Leonard tries again with Penny. She is pigging out on ice cream and chocolate sauce and wondering if she either picks giant losers, or, picks great guys and turns them into giant losers. She names a long list of people who have already read the blog, from friends to family to prisoners at a state penitentiary. She tells Leonard that he might as well read it too. He scans the blog and tells Penny that she doesn't need to be embarrassed; it just paints a picture of Penny as an affectionate woman who prefers affection in non-traditional locations. Penny thinks that she may be over-reacting, while Leonard thinks she should be done with Mike due to his betrayal. Penny wants to give him a chance to explain, wondering if this is just Mike's poorly chosen way to express how he feels about her. She thanks Leonard for helping her to see it, and heads over to see Mike. Leonard is left in her apartment looking very unhappy.

The Tangerine factor - 4 eating food

Game night and dinner.

Back at the apartment, the boys are eating Chinese food and playing Talisman, 4th edition; and Sheldon notes that he must need more Mandarin lessons, as he's still not getting tangerine chicken. Leonard is lamenting that his intervention made things worse for himself by fixing Penny's issue over Mike. Howard remarks that the story gets better every time Leonard tells it. Sheldon disagrees, because while the first telling was compelling, causing him to feel sympathy, but he now finds the "Leonard character" to be whiney and annoying.

Penny sticks her head in to yell at Leonard "thanks for your stupid advice". Leonard goes to her apartment and Penny tells Leonard that Mike had already moved on - he had some other woman there with her legs wrapped around his neck. She cries that she wants to go out with someone nice and honest and who cares about her. Leonard asks "what about me?" And Penny thinks about it a moment and then says "yes", noting "What do I have to lose?". Leonard attempts not to be insulted, groaning "That's the spirit".

The Tangerine Factor 43

Why don't you go out with me?

The next day, Sheldon is still trying to learn key Chinese phrases with which to interrogate the local restaurant. Penny tries to talk to Sheldon about going out with Leonard. Sheldon tries to convince Penny that he really isn't an expert on Leonard, being frequently surprised by Leonard's actions and behaviors; from Leonard hiding his loofa, to Leonard being able to tolerate small amounts of non-fat ice cream without emitting noxious gas that could be weaponized. Fearing that Leonard may come home and discover her talking to Sheldon about him, Penny invites Sheldon into her apartment to continue the conversation. Sheldon, surprised that the conversation is not already over, accepts the invitation, noting that "we're already through the looking glass."

Penny assumes that Sheldon is aware that Leonard asked her out. Sheldon was wise to this when Leonard returned to the apartment behaving in a way that reminded Sheldon of the dancing hippos from Fantasia. She invites Sheldon to sit down, but he hasn't been in Penny's apartment often enough to evaluate cushion density, airflow patterns, and dispersion of sunlight to make an informed choice about WHERE to sit. He tells Penny to go ahead and talk while he makes these evaluations. Penny notes that she's aware that Leonard has a "little crush" on her. Sheldon finds that amusing..."in the same way that Menelaus had a crush on Helen of Troy" (sparking the Trojan War).

The Tangerine Factor 41

You look nice.

Leonard isn't the kind of guy Penny usually goes out with, and she's concerned that if things don't go well, she's risking their friendship. Sheldon points out that Leonard isn't the type of guy that anyone usually goes out with. Penny notes that her choices haven't been working out, and that maybe Leonard is different in a good way. Sheldon tries to use the conundrum of Schrödinger's Cat (used to illustrate the Copenhagen Interpretation of Quantum Physics) to reflect the state of the relationship between Penny and Leonard. The cat was placed in a box with a vial of poison that would open at a random time. From the outside, no one could know whether the cat was dead or alive until they actually opened the box, and until that happened, the cat could be thought of as BOTH dead AND alive. Sheldon points that to Penny that until she and Leonard actually DO date, their relationship and the outcome of dating can be interpreted as both good and bad. Back at the university cafeteria, Leonard and Sheldon discuss the upcoming date. What if he blows his one chance to date her? Sheldon notes that it would likely result in Leonard becoming a lonely, bitter, old man with no progeny; "a number of evil lighthouse keepers from Scooby Doo cartoons comes to mind".

TTF First Date Kiss

Leonard kisses Penny. OK. The cat's alive.

Later at the cafeteria, Leonard also seeks Sheldon's advice on dating Penny. He merely says "Schrödinger's Cat" and Leonard understands.

Penny and Leonard meet the next night for their date, but Penny wants to talk first. Leonard then asks her if she ever heard of Schrödinger's Cat, to which she says that she's heard far too much about it. Satisfied, he kisses her. Finally understanding what Sheldon tried to tell her, Penny proclaims that "the cat's alive" (she feels a connection with Leonard) and they rush off to dinner.

Penny n Leonard Leave restaurant

Leonard and Penny enter the Szechuan Palace and leave when they see Sheldon making a scene.

Sheldon is at Szechuan Palace, arguing with the manager about the Tangerine Chicken, however his incredibly flawed Mandarin leads the manager to think Sheldon is crazy, and he threatens to call the police. Sheldon doesn't realize that he's speaking the language incorrectly and thinks that their annoyed behavior and their refusal to answer his questions prove that he's right about the Tangerine Chicken. Leonard and Penny avoid entering the place and running into Sheldon in the last moment.




  • Title Reference: Sheldon is afraid that the Szechuan Palace's Tangerine Chicken is using another fruit besides tangerine.
  • Chuck Lorre's vanity card [1]
  • This episode was watched by 7.34 million people with a rating of 3.2 (adults 18–49).
  • Episode transcript [2].

Costume Notes[]


Bat Question


Triple Threat

S01e17 recordplayer

Turntable by Heavy Rotation


Red Shards


Superman belt buckle


Detail of Turntable shirt

Sheldon wears his Riddler: Bat Question shirt, as well as "Triple Threat", a blue large plaid patterned t-shirt by Kirra (discontinued). He actually has this same shirt in multiple colors including light blue plaid on black. Leonard wears his light blue shirt featuring a record turntable from Heavy Rotation (discontinued), and his red "shards" t-shirt. Howard wears his Superman logo belt buckle.

Set Notes[]


New on the set: 20x20 Ikea throw pillow, Gurli Solid Orange.


  • Penny dumps Mike, who was previously shown in "The Nerdvana Annihilation" (S1E14).
  • The exchange concerning the Damsel In Distress and the need for Leonard to be knighted for it to apply was originally used, verbatim, in the Unaired Pilot, although in a completely different context.
  • "Through the Looking Glass" was Lewis Carroll's sequel to "Alice In Wonderland". Like Alice, it too has a strong chess-centered theme. Alice goes through the looking glass, i.e. mirror, to another world where things are recognizable, yet turned sideways. The phrase "through the looking glass" is a metaphor for any time the world turns strange, insane, or otherwise abnormal, as if one were on the other side of the mirror. A free e-book (including Kindle) version of "Through the Looking Glass" is available as a free download at Through the Looking Glass is also a national research and support organization for families of children with disabilities, and the title of an album by British punk band, Siouxsie and the Banshees.
  • The 'little crush' that Menelaus had on Helen Of Troy was enough to launch the Trojan War when Paris stole her away.
  • The Schrödinger's Cat analogy recurrent through the episode is mentioned again in "The Codpiece Topology", wherein Penny mentions it to a guy she goes out with, as well as in "The Russian Rocket Reaction", wherein Sheldon refers to "Schrödinger's Friendship". Learn more with In Search of Schrödinger's Cat: Quantum Physics and Reality.
  • Sheldon is correct in stating that light years are a measure of distance, not time.
  • The Chinese food restaurant is not seen again until the third season's episode "The Bozeman Reaction".
  • This is the only season finale to be episode 17 rather than 23 or 24.
  • The board game that Howard, Sheldon, Leonard and Raj are playing in the scene where they are eating Chinese food is Talisman: The Magical Quest Game, 4th Edition. It also appears in the previous episode, "The Peanut Reaction". They make numerous mistakes while playing: having too many pieces, using the wrong counters, having face down cards strewn about the board and rolling two dice to move their piece.
  • Sheldon says, "You also made a common grammatical mistake, you said nauseous when you meant nauseated". According to Merriam Webster Usage Discussion of NAUSEOUS, such an insistence is a mistake.
  • First episode where Leonard and Penny were shown to be in a relationship.
  • In the cafeteria scene with Leonard and Sheldon, Sheldon picks up a salt grinder and "shakes" salt onto his food then does the same with a pepper grinder.
  • This is the lowest rated episode of the series even though it's Leonard and Penny's first date.
  • One of two appearances by veteran Asian actor James Hong.


  • When Penny threw Mike his iPod, why did she do it at Leonard and Sheldon's? Of the two apartments, Penny's is the one located above the building's entrance and with its windows facing Los Robles Avenue.


Sheldon: (Quoting incorrect Mandarin) "Show me your mucus, your mucus."
Chen: (In Mandarin) "Blow your own nose and go away."
Sheldon: "This is not tangerine bicycle."
Chen: (In English) "Crazy man. Call the police!"
Sheldon: "No, don't call the library, show me your mucus. Oxen are in my bed. Many, many, oxen."
Chen: (Shoos him away) Ha!
Sheldon: "Oy vey!"

Howard: You know, I’m really glad you decided to learn Mandarin.
Sheldon: Why?
Howard: Once you’re fluent, you’ll have a billion more people to annoy instead of me.

Leonard: Penny, are you okay?
Penny (voice off): I’m fine, Leonard, just go away.
Leonard: Look, I understand that breaking up with someone can be very painful….
Penny: GO AWAY!
Leonard: Okay, feel better, bye. (Goes back to apartment) She doesn’t want to talk.
Sheldon: Not surprising. Penny’s emotional responses originate from the primitive portion of the brain known as the Amygdala, while speech is centred in the much more recently developed Neocortex. The former can easily overpower the latter giving scientific credence to the notion of being rendered speechless. (Leonard stares at him.) Or maybe she just doesn’t want to talk.
Raj (entering): Hey, look, I found an iPod.
Howard: It’s smashed beyond repair, what are you going to do with it?
Raj: What else? Sell it on ebay as slightly used.
Leonard: It was Penny’s boyfriend’s, they broke up.
Howard: Apparently he posted intimate details of their physical relationship on his blog, which I cannot find anywhere.
Leonard: You know what, I’m going to go back and try talking to her again.
Howard: Good idea. Sit with her, hold her, comfort her, and if the moment feels right, see if you can cop a feel.
Leonard: I’m not going to do that, Howard.
Sheldon: I’m not aware of any social convention that requires you to intervene at all.
Leonard: What about “damsel in distress?”
Sheldon: Twelfth century code of chivalry, not exactly current. You’d also have to be knighted for that to apply.
Leonard: I don’t care. She’s upset, I’m going over there.
Howard: Remember to sit on your hands a bit so they’re warm.
Leonard: I’m her friend, I’m not going to take advantage of her vulnerability.
Howard: What, so you’re saying that if in the depths of despair she throws herself at you and demands you take her, right there, right now, you’ll just walk away?
Leonard: I said I’m her friend. Not her gay friend.

Leonard (knocking and entering): Hey, listen, I know you said that you didn’t want to talk…
Penny: (she shouts through her mouthful of ice cream) I don’t.
Leonard(starts leaving) Sorry.
Penny: Wait.
Leonard: Wait, did you say wait?
Penny: Tell me the truth. Am I just an idiot who picks giant losers?
Leonard: No. No.
Penny: Okay, so I pick good guys, but turn them into losers?
Leonard: Of course not.
Penny: Well, it’s got to be one or the other, which is it?
Leonard: I’m sorry, what were the choices again?
Penny: I really thought Mike was different, I thought he was sensitive and smart. I mean, not you smart, normal non-freaky smart.
Leonard: Yeah, no, sure.
(Penny pours some chocolate syrup on her ice cream furiously)
Penny: You know, and then he just goes and has to humiliate me by writing about me on his blog so the entire world can read it.
Leonard: Actually it’s not all that easy to find.
Penny: Yeah, really, well my friends at work found it, my sister found it, judging by my email a number of prisoners at the Michigan State Penitentiary found it.
Leonard: Okay, well, what exactly did this guy write, not that I need to know the details of your sex life, I just thought…. never mind.
Penny: Nope, you know what, you might as well read it, everybody else has, go ahead. (Leonard goes to the computer while she's almost in tears) Oh God, I just feel so betrayed and embarrassed. I just want to crawl into a hole and die. (she squirts some whipped cream into her mouth sadly)
Leonard: Okay, well, you know, this isn’t that bad. It just paints the picture of a very affectionate woman who’s open to expressing her affection in non traditional locales.
Penny: Oh God!
Leonard: Elevators, parks, movie theatres, out of curiosity, is this subway the transportation system or subway the sandwich shop?
Penny: Sandwich shop.
Leonard: Doesn’t that violate the health code?
Penny: No, at the sub shop we were only making out.
Leonard: Huh. Okay. But my point is that you have absolutely no reason to be embarrassed.
Penny: Really, do you think I overreacted?
Leonard: Maybe a little.
Penny: ‘Cause I do that, I do overreact. Maybe I should call Mike and apologise.
Leonard: No. No, no, that, that would be underreacting. He did break the implied confidentiality of the bedroom and, in your case, the elevator, parks and fast food franchise.
Penny: Yes. You’re right. I should just say I’m done with him.
Leonard: Yes, you should, go ahead, say it.
Penny: But I never gave the man a chance to explain.
Leonard: What is there to explain, it’s all right here, it’s a betrayal.
Penny: No, you were right the first time, this is a man who loves me, but in his own stupid way he was just trying to show people how he feels.
Leonard: I’m pretty sure I never said that.
Penny: No, you did better than that, you helped me see it on my own.
Leonard: Aw, good for me. Where are you going?
Penny: I’m going over to Mike’s. Leonard, thank you so much.
Leonard: Oh, sure. Huh, maybe I am her gay friend

(The scene where the extremely upset Penny storms into Apartment 4A be more angry with Leonard for one second)
Penny: (angrily yells at Leonard) Thank you so much for your stupid advice!
(Penny slams the door again and Sheldon, Howard and Raj now turn their heads in shock to the very depressed Leonard)
Raj: (He speaks to Leonard in surprise) Incredible. You managed to screw up the screw-up. (turns back to the board game)

Leonard: (knocking and entering) I’m back.
Penny: (now on the verge of tears) I’m sorry I yelled at you. It’s not your fault.
Leonard: What happened?
Penny: Well, I went over to Mike’s to make up with him.
Leonard: Yeah, I know, I know that part.
Penny: But he had already moved on.
Leonard: Already, that was quick.
Penny: That’s what I said to the woman who had her legs wrapped around his neck. (starts to cry)
Leonard: Oh, Penny, I am so sorry.
Penny: How could he do that?
Leonard: Oh, well, you know, you did throw an 8 gig iPod (Penny turns to him)… yeah, no, how could he do that?
Penny: I swear to God, I am done with guys like that. You know, macho, with the perfect body and the hair, and the money.
Leonard: (slight sarcasm) Yeah, that must get old quick.
Penny: You know, just once, I would like to go out with someone who is nice, and honest, and who actually cares about me.
Leonard: What about me?
Penny: What about you, what?
Leonard: What about if you went out with me?
Penny: Are you asking me out?
Leonard: Um… yes… I am… asking you out.
Penny: Wow.
Leonard: I was just going off your comment about the nice guy…
Penny: No, I know, I got that. Yeah, totally.
Leonard: (continuing through Penny): …thing and honest but, it’s no big deal…
Penny: Yes.
Leonard: Yes what?
Penny: Yes, I will go out with you.
Leonard: Really?
Penny: Yeah. Why not, I mean, what do I have to lose?
Leonard: Yeah. That’s the spirit.

Penny: Sheldon, do you have anything to say that has anything to do with, you know, what I’m talking about?
Sheldon: Well, let’s see. We might consider Schrödinger’s Cat.
Penny: Schrödinger? Is that the woman in 2A?
Sheldon: No. That’s Mrs Grossinger. And she doesn’t have a cat, she has a Mexican hairless, annoying little animal, yip yip yip yip…
Penny: Sheldon!
Sheldon: Sorry, you diverted me. Anyway, in 1935, Erwin Schrödinger, in an attempt to explain the Copenhagen interpretation of quantum physics, he proposed an experiment where a cat is placed in a box with a sealed vial of poison that will break open at a random time. Now, since no-one knows when or if the poison has been released, until the box is opened, the cat can be thought of as both alive and dead.
Penny: I’m sorry, I don’t get the point.
Sheldon: Well of course you don’t get it, I haven’t made it yet. You’d have to be psychic to get it, and there’s no such thing as psychic.
Penny: Sheldon, what’s the point?
Sheldon: Just like Schrödinger’s Cat, your potential relationship with Leonard right now can be thought of as both good and bad. It is only by opening the box that you’ll find out which it is.
Penny: Okay, so you’re saying I should go out with Leonard.
Sheldon: No, no, no, no, no, no. Let me start again. In 1935, Erwin Schrödinger…

(Leonard knocks on Penny's door.)
Penny: Hi.
Leonard: Hi.
Penny: come on in.
Leonard: Thank you. You look very nice.
Penny: Thank you. So do you.
Leonard: I made an eight o’clock reservation.
Penny: Okay, great, listen, um, maybe we should talk first.
Leonard: Oh. Okay. But before you say anything, have you ever heard of Schrödinger’s Cat?
Penny: Actually, I’ve heard far too much about Schrödinger’s Cat.
Leonard: Good. (He grabs her and kisses her)
Penny: Alright, the cat’s alive, let’s go to dinner.

[The really furious Penny comes storming in to the apartment during the opening scene]
Penny: I need to use your window.
Leonard: Oh, yeah, no, sure, go ahead.
Penny: (opens the window to yell with loud anger) Hey Jerkface, you forgot your iPod!
(angrily throws it out the window. Leonard hears a small sound of the iPod crashing onto the street and Penny slams the window in a rage).
Leonard: What’s going on?
Penny: Oh, I’ll tell you what’s going on, that stupid self-centred bastard wrote about our sex life in his blog. (from the window) Drop dead, you stupid self-centred bastard! (To Leonard) Thank you. (exits the apartment)
Sheldon: Okay, where were we?
Howard: Not now, I have a blog to find.