The Big Bang Theory Wiki

"The Decoupling Fluctuation" is the second episode of the sixth season of the American sitcom The Big Bang Theory. This episode first aired on Thursday, October 4, 2012.[1]


Penny is starting to have doubts about her relationship with Leonard, while Stuart is added to their group as a replacement for Howard, who is in orbit on the International Space Station.

Extended Plot[]

At Bernadette's apartment, Penny and Amy are helping her sort through her wedding presents. Sheldon's gift, a gravy boat, is engraved with instructions to return it should the couple get divorced. Penny thinks Sheldon's comment is inappropriate, but wonders why she did not think of adding them in the first place. When the subject of marriage comes up, Amy says that she plans on marrying Sheldon in four years, but she tells Bernadette to not tell Sheldon about it because he is still a flight risk. When Penny is asked about Leonard, she keeps saying that he is a great guy. Bernadette thinks that Penny does not sound like she is in love and asks her about it. Penny admits that the feelings she has for Leonard are not the same as the feelings she had when she was in love before. She concludes that maybe it is a new, better, boring kind of love. Also, she doesn't want to tell him that she loves him because he would just take it the wrong way. She's not sure that it is the real thing, or how Leonard would react if she told him or that she will stay together with him.

The Decoupling Fluctuation Sheldon, Leonard and Raj

Talking to Howard in space.

Meanwhile, Raj, Leonard, and Sheldon are talking to Howard at the International Space Station and Howard tells them he cannot believe that he is on this incredible adventure. His Russian crew member then tells him to go clean the space toilet since he is the new guy; and that next time, they might even let him use a brush.

The Decoupling Fluctuation At The Cinema

The gang at the movies.

The gang, minus Bernadette (who doesn't come), goes to a movie and Stuart tags along, claiming that Raj invited him. Sheldon insists that he acts just like Howard would and among them, he has to eat Raisinets. He also asks Stuart where he went to school to compare him to Howard. Stuart attended an art school, which Sheldon thinks is equally ridiculous as Howard's education so Stuart passed his test. During the movie, Amy insists that Sheldon holds her hand, which he hesitantly obliges to do. He sees that Leonard is not holding Penny's hand. Amy tells Sheldon that there may be a reason for that and tells him that Penny may be breaking up with him. Sheldon does not believe her because Penny is seen drinking Leonard's diet (and germy) Dr. Pepper. Amy tells him things are complicated, but he does not agree with her as a complicated matter would be the string theory. For the sake of argument, Sheldon asks Amy what she means about Penny wanting to break things off with Leonard. Amy tells him that Penny is not sure how she feels about Leonard. Sheldon finds it preposterous for a person to not know how she feels, because he is certain about what he likes and dislikes. (Handholding, no; fish with tools on their noses, yes) Amy tells him that regardless, he has to keep it a secret, something Sheldon openly admits he does not like to do. Just then Stuart offers Sheldon Raisinets, to which he points out that Stuart is disrupting them trying to watch a movie, and he tells Amy that he does not think Stuart can fit in with their group after all.

Later in Sheldon and Leonard's apartment, Sheldon is in a dilemma about whether or not to tell Leonard about the secret. Leonard gets annoyed by Sheldon's restless behavior and does not mind even if Sheldon decides to keep quiet about it; however, Sheldon succumbs and decides to tell Leonard anyway. He uses Transformers as an analogy about Leonard's relationship with Penny, by telling him that what he sees outside can mean a different thing inside, just like how their current conversation about Transformers can actually be regarding one of them in the room. Leonard tells Sheldon that he gets it, but misinterprets Sheldon's words as pertaining to him and how he used to be a heartless robot, but after meeting Amy he maybe becoming a red-blooded man with sexual desires. Sheldon tells Leonard that that was the stupidest thing he has ever heard.

S6EP02 - Sheldon in Penny's bedroom

Sheldon goes into Penny's bedroom.

Sheldon attempts to tell Leonard again during the early morning hours, but instead he goes into Penny's bedroom waking her up as she screams hysterically. Sheldon beats around the bush telling Penny about Leonard's great attributes as a boyfriend, until Penny asks him what Amy had said. Sheldon replies that he had heard that she was thinking of breaking up with Leonard. Penny patiently tells him that it is sweet that he is worried about his friend, but that her relationship is none of his business. He asks her to keep dating Leonard no matter how she feels and to keep everything in "homeostasis" or unchanging, the way that Sheldon likes his life. He also wants her to change her shampoo from coconut back to green apple. Finally Sheldon leaves and asks her "not to hurt my friend". Penny responds that that is the last thing she wants to do.

Amy gets an early morning phone call from Penny complaining that because of what she had told Sheldon, she was now in a terrible position. At the same time, an incoming call from Sheldon comes and he tells Amy that he is calling just to give her the heads up since he has told Penny about the secret. Amy says that Penny is already on the other line, making Sheldon say that everything is now fine now that everyone is on the same page.

Walowitz would never play that card

I'm sorry. Wolowitz would never play that card.

S6EP02 - Howard confesses

Howard confesses to Bernadette about how the astronauts are treating him.

Bernadette is talking to Howard at the ISS who complains about his fellow astronauts being mean to him. She tells him to stand up and tell them that "being mean is lame, but being nice is cool". She asks if she should call NASA, and Howard replies that his mother already did that and it made things worse.

Stuart is playing Mystic Warlords of Ka'a with the rest of the gang and plays a card that Sheldon says Howard would not play. After changing cards, Sheldon goes out and wins. Stuart and Raj are going out to a bar to pick up women. Sheldon suggests that Leonard go along to find a back-up for Penny because of her illogical death-defying actions, though he thinks that they may be breaking up.

Sad eyes

Leonard's saddest eyes ever.

Later Penny and Leonard are having dinner at her place. While Leonard is telling her about Sheldon's misadventures at the dentist, Penny seems very distracted. Finally she says that she has to tell him something. Leonard sits back, looks at her with what Penny describes as his big sad eyes and she appears conflicted again.

Later, at Howard and Bernadette's Apartment, she tells the girls about what happened and Amy exclaims, "You slept with him?" Penny says that she was looking into his big sad eyes and could not tell him. Penny demonstrates and Amy replies that it is a good thing that she does not have a dog. Bernadette tells her that she will have plenty of times to break-up with him like on their wedding day, their honeymoon or their 50th anniversary. Penny insists that they aren't getting married and that they'll keep their relationship in a homeostasis condition. Amy thinks that she is cute when she tries to use scientific terms. Leonard texts her telling her how amazing she is while Amy and Bernadette look at her with big sad eyes.


I finally had the best night's sleep ever.

Finally Bernadette is again talking to Howard about how her idea worked and that he got a great night's sleep. Unbeknownst to him, his fellow astronauts had drawn a mouse's face, whiskers, glasses and his nickname "F. LOOPS" on his face. Bernie gives him a "proud" face and does not tell him that she knows.



  • The TV Critic: "Sheldon is a funny character and even though this was repetitive material the odd line still worked. This was absolutely classic Big Bang Theory... I can’t argue that the writers aren't addressing the Penny and Leonard relationship. But they are spinning their wheels frantically to make sure it looks like something is happening while no momentum is gained...Same old, same old. Come on Chuck Lorre. Will people really stop watching if something interesting happens?"[2]
  • The A.V. Club gaves this episode a C.[3]
  • IMDB user reviews


  • Title Reference: The title of this episode is derived from the on-off status of Leonard and Penny's relationship, with Penny once again considering of breaking up with Leonard even though they just rekindled their romance in "The Recombination Hypothesis".
  • Chuck Lorre's vanity card.
  • This episode was watched by 15.18 million people with a rating of 4.9 (adults 18–49).[4]
  • Total viewers including DVR users 18.99 million.
  • This episode aired in Canada on October 4, 2012. with 3.94 million viewers and a weekly ranking of #1.[5]
  • In the United Kingdom, this episode aired on November 22, 2012, with 2.565 million total viewers.[6]
  • Episode transcript [1]

Costume Notes[]

  • Sheldon wears his orange Aquaman II t-shirt and the blue urban Outfitters t-shirt with the green angled gradient stripes.
  • Bernadette wears a rose print dress from Forever21 (no longer available).
  • Penny's floral and lace top by Candies is no longer available from Kohl's.


  • First physical appearance of Bernadette this season; she only appeared via Skype in the previous episode.
  • Bernadette does not share any scenes with Sheldon, Raj, Stuart and Leonard in this episode.
  • First appearance of the bedroom in Amy's Apartment.
  • Sheldon's inability to keep a secret is again shown in this episode.
  • Bernadette does not come to the movies with Penny, Amy and the four guys. She might be busy worrying about her husband Howard and doing different stuff that night. She might not want to go out with Stuart, Raj, Sheldon or Leonard while Howard (her hubby) is away in space.
  • This is the third time where Sheldon has knocked three times while Penny is sleeping, causing her to scream in terror; the first was in "The Einstein Approximation" (S3E14) and the second was in "The Precious Fragmentation" (S3E17 - Penny punched Sheldon in this instance).
  • Bill Prady tweeted that a post-show backstage party was organized for the Mars Rover Landing Team after the taping of the episode, with pictures of Kevin Sussman (Stuart) and Steven Molaro caught together with the team too.
  • In "The Countdown Reflection" (S5E24), Sheldon mentioned that he bought an $88 gravy boat as the wedding gift for Howard and Bernadette. The gravy boat appears in this episode.
  • Bernadette only has two scenes with Penny and Amy in this episode.
  • Mayim Bialik's injury is not written into the episode, with writers opting to hide her injury instead, just as they did with Kaley Cuoco's Penny when she broke her leg during the fourth season.
  • While on the International Space Station, Howard is forced by fellow astronauts Mike Massimino and Dimitri Rezinov, who are giving him a hard time as the new guy, to clean the toilet. Mike says, "You want to see the meteor shower? Look at what Dimitri left for you in the toilet." This time is probably an ironic reference to Howard's Wolowitz Zero-Gravity Waste Disposal System which went terribly wrong in "The Classified Materials Turbulence".
  • To assess the potential of Stuart as a replacement for Howard, Sheldon inquires about Stuart's education, with Stuart stating that he went to art school. In "The Hofstadter Isotope", Leonard explained to Penny that he's a terrific artist and attended the Rhode Island School of Design.
  • Sheldon inquired if Penny knew that "while Leonard is not considered a tall fellow in our country, in today’s North Korea, he’s downright average." Since the average male height in North Korea is currently 5 ft 5 in (1.656 m),[7] Leonard's height is known. Indeed, this measurement is consistent with actor Johnny Galecki's height of 5 ft 5 in (1.65 m).[8]
    • Assuming an exact correspondence between the character's height and that of the portrayer, the rest of the main character heights are as follows: Sheldon (Jim Parsons) stands 6 ft 1 in (1.86 m),[9] Raj (Kunal Nayyar) stands 5 ft 7 in (1.70 m),[10] Penny (Kaley Cuoco) stands 5 ft 6 in (1.68 m),[11] Howard (Simon Helberg) stands 5 ft 4 in (1.63 m),[12] Amy (Mayim Bialik) stands 5 ft 4 in (1.63 m),[13] and Bernadette (Melissa Rauch) stands 4 ft 11 in (1.50 m).[14] (NOTE: Average male height in the U.S. is 5 ft 9 in (1.763 m) and average female height in the U.S. is 5 ft 4 in (1.622 m), while the average height of males in India is 5 ft 5 in (1.647 m)).
  • Sheldon tells Penny that "Leonard has a perfect driving record". It should be noted that, at the end of "The Love Car Displacement", Leonard drives at 120 mph, and is noticed and approached by the police. Also, in "The Zarnecki Incursion" (S4E19), Sheldon berates Leonard for driving above the speed limit.
  • At the end, when Howard is video chatting with Bernadette, he has no idea that he has writing on his face, although you can see yourself on Skype.
  • Penny can't resist Leonard's big puppy dog eyes.
  • Mystic Warlords of Ka'a cards played and declared in this episode: "Gelatinous Sphere", "Focused Locust" (apparently an insect with good concentration), "Temple of Yip", "Lesser Demon-Turtle", and "Fairy God Monster".
  • Amy wants a real human skeleton, but cannot afford one, as they are expensive. She, therefore, plans to register at the anatomy lab to obtain one as a wedding gift when she eventually marries. While Amy sometimes displays odd interests, real skeletons (or pieces thereof, such as skulls) are actually available for ownership; they are often owned by anatomy labs, medical schools, etc., as plaster replicas, while typically sufficient for primary and secondary education, may not be accurate enough for the training of professionals. As Amy is a biological scientist, owning a skeleton is actually not such an outlandish wish.
  • Amy claims that she has a four-year plan to Sheldon to marry her. They actually get married four years and seven months later in May 2018.
  • Like with Howard and Bernadette, rumors fly as to whether they are going to break-up or not.
  • Sheldon again to his dismay has to keep a secret and a personal manner.


(The opening scene of the girls at Bernadette's apartment)
Bernadette: And the next wedding gift is a gravy boat.
Penny: Ooh, one gravy boat.
Amy: That’s from Sheldon. He told me he had it engraved.
Bernadette: In the event of a divorce, please return to Sheldon Cooper.
Penny: One inappropriate, yet I wish I thought of that gravy boat.
Amy: When I get married I’m going to register at the UCLA Cadaver Lab.
Penny: Ew, why?
Amy: ‘Cause I’ve always wanted a whole human skeleton and they are really spendy.
Bernadette: So, you actually see you and Sheldon getting married someday?
Amy: Not just someday. In exactly four years. But don’t tell Sheldon. He’s still a flight risk.
Bernadette: What about you, Penny?
Penny: What about me what?
Bernadette: Do you think you and Leonard might ever get married?
Penny: Oh, well, you know, Leonard is great.
Bernadette: But do you think you’ll ever get married?
Penny: He’s a sweetie.
Amy: You’re not answering the question. Do you love him?
Penny: Yeah, sure, of course I love him.
Bernadette: It doesn’t sound like it.
Penny: Well, I do.
Bernadette: Do you tell him that?
Penny: No, he’d just take it the wrong way.
Amy: What does that mean?
Penny: It means he is special and smart and nice and…
Bernadette: Are you gonna break up with him?
Penny: No. Maybe. I don’t know.
Bernadette: I had no idea you were unhappy.
Penny: That’s the thing, I’m not. I’m not unhappy at all. It’s just, I don’t know, I, I’ve been in love before, but it felt different. But maybe this is a new, better, boring kind of love. Do you ever feel that way about Howard?
Bernadette: Oh, that’s not really a fair comparison. I’m basically married to a sexy Buzz Lightyear.
Penny: Amy, you?
(Penny and Bernadette look happy at each other)

(The cinema scene where Amy is firm with Sheldon)
Amy: Regardless, don’t say anything to Leonard.
Sheldon: Now you’re asking me to keep a secret from my best friend, colleague, and roommate?
Amy: Yes, please, Penny will kill me.
Sheldon: (groans) Fine, but FYI, secret-keeping: Hate it. Hand-holding, not a fan. Hammerhead shark, I love that thing. Another fish with a tool on its head.

(The cutting scene between the International Space Station and Bernadette’s apartment)
Howard: Hey, Bernie.
Bernadette: There’s my hubby. How’s everything going up there?
Howard: Oh, it’s okay. Space is beautiful. Earth is beautiful. Same old, same old.
Bernadette: (Suddenly worried) What’s wrong?
Howard: Nothing. Everything’s fine.
Bernadette: (grunts crossly) Howard.
Howard: The other astronauts are being mean to me.
Bernadette: No, what are they doing?
Howard: Well, like for instance, the other day when I was asleep, one of the guys went on a space walk and glued a big-eyed rubber alien mask to the outside of my window. When I woke up, I screamed for like nine minutes.
Bernadette: (mega-fully upset) Oh, Howie.
Howard: You can see it if you want. It’s on YouTube. Google astronaut screams for nine minutes.
Bernadette: Why don’t you stand up to them?
Howard: (chuckles for a bit) What am I supposed to say?
Bernadette: I don’t know. Say, being mean is lame, what’s cool is being nice.
Howard: Great, I’ll do that when I want to be the first guy in space to get a wedgie.
Bernadette: Do you want me to call somebody at NASA?
Howard: No. My mom already tried that. It only made things worse.

Sheldon: Please don't hurt my friend.
Penny: That is the last thing I want to do.
Sheldon: Thank you. Coconut? What were you thinking? Are you a hula girl?
Penny: Get out.

(The scene in Amy's apartment bedroom where Amy's mobile phone is ringing on her bedside table in her apartment)
Amy: Hello?
Penny: What the hell is wrong with you? You told Sheldon? Do you know what a terrible position this puts me in? (Phone beeps)
Amy: Hang on, please. Hello?
Sheldon: Yeah, just a heads-up: Penny knows that you blabbed about Leonard. She’s pretty mad.
Amy: I know. She’s yelling at me right now.
Sheldon: All right then, so we’re all on the same page. Yes.
(Sheldon ends his call to Amy and puts his phone down onto the desk. He now gets out of the chair)

(The scene at Apartment 4A where Leonard has just had a thought)
Leonard: Okay, I think I understand.
Sheldon: You do?
Leonard: The guy who seems like an emotionless robot is you, (Sheldon doesn't know how to describe that emotion) but your relationship with Amy is causing you to transform into a red-blooded man with sexual desires.
(Sheldon reacts crossly at the strong words that Leonard had said)
Sheldon: That is literally the stupidest thing I've ever heard.
(Sheldon now gets up off the chair in a huff)

(The scene at Bernadette's apartment)
Amy: (asking Penny crossly) You slept with him?
Penny: I didn’t know what else to do. He had those big, sad eyes.
Bernadette: Oh, sure, you had no choice.
Penny: He looked at me like this.
Amy: Well, if that’s all it takes, it’s a good thing you don’t have a dog.
Bernadette: Don’t worry. You’ll have plenty of chances to break up with him. Your wedding day, your honeymoon, your 50th anniversary.
Penny: Look, it’s fine. We’re not getting married, okay? We’re keeping things, you know, homeostasis.
Amy: It’s so cute when she tries.
Penny (phone text tone) : It’s from Leonard. Last night was amazing. You’re amazing. I’m so lucky to have you in my life. (They give him a hangdog look) Okay, stop it.

(The ending scene with a cutting between the International Space Station and Bernadette’s apartment)
Howard: (out of vision on Skype) Hey, Bernie, guess what? I stood up to the other astronauts like you said and I got to tell you, last night was the first time in a week I got a good night’s sleep. (On screen, Howard has a mouse face drawn on his face, and the words F.LOOPS on his forehead.)
Bernadette: Oh, Howie.
Howard: What’s wrong? You look upset.
Bernadette: Nope, this is my proud face.
(Howard grins and puts his thumb up sign at the proud Bernadette)


See also[]