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"The Collaboration Fluctuation" is the nineteenth episode of the tenth season of the American sitcom The Big Bang Theory. The episode aired on Thursday, March 30, 2017.


Leonard, Penny and Raj adjust to their new living arrangement, and Sheldon begins working with Amy.

Extended Plot[]

Raj and Penny are practicing yoga in the apartment when Leonard asks Penny about their pre-work breakfast date. Leonard then backs down as Raj asks him if he could take Cinnamon for a walk. Leonard leaves the apartment momentarily and returns saying that Cinnamon is done, having peed on him.

Going to work Sheldon tells Amy how well things are going with the guys’ gyroscope project and then realizes that any further details are classified. Sheldon asks Amy about her work. She is working to pinpoint where consciousness resides in the brain. Her hypothesis is that the signal to move a muscle occurs before one even makes the decision to move it.


Matching buddies.

In the Caltech cafeteria, Sheldon sits down with the guys and tells them how he just picked up a spoon without thinking about it. When did he decide that? Oooo. He tells them how Amy is studying the time lag between intent and awareness which Sheldon finds interesting.

At the Hofstadters', Raj and Penny discuss her office politics which Leonard can't follow because she has never mentioned some of these people to him.

Amy returns home lugging her harp after a lesson and wondering if it's the best instrument to play when she has to walk up four fights every day. Sheldon is working at a whiteboard trying to prove her hypothesis using neuroscience and quantum mechanics. They could disprove the role of consciousness in the Copenhagen interpretation. Amy is interested in working with Sheldon, but she wants to lay some ground rules so that their relationship isn't affected.

Back in apartment 4A, Leonard is uncomfortable as Penny and Raj wear moisturizing face masks. Penny then suggests that they all do something together. Raj wants to go shopping. Leonard wants to play a board game which doesn't excite the others. While shopping Leonard ends up holding Penny's purse, while Raj and Penny sample makeup. Back at home, Raj and Penny are seen wearing matching shirts.

Sheldon has the first attempt at ground rules that only favor him. Amy throws his rules out the window and says that she'll write them.

Meanwhile, Leonard joins Howard and Bernadette on a shopping trip for diapers. He complains about being a third wheel in his own home.

Back at Sheldon and Amy's, he's gotten his notebook back, but it's been vandalized. After he agrees to Amy's rules, they happily get to work though later they both agree that their progress was garbage.

At a supermarket, Leonard complains how Raj's closeness with Penny was making him uncomfortable. Bernadette asks Leonard if he's talked to them, but he doesn't want them to stop having fun. Then he starts getting jealous of Penny since Raj was his friend first.

Sheldon and Amy wonder what went wrong n their calculations. As they get irritated and they start insulting each other. Their conflict inspires Sheldon to see what's wrong with one of their equations.



Raj and Penny are having wine while he admits that he is having a rough time and that staying there has taken his mind off of it. Penny has loved having him around and when she asks Leonard to agree, she realizes he is not even in the apartment.

Driving back Howard reminds Leonard that Penny has someone to do the things which her that Leonard doesn't want to. Bernadette admits that he is allowed to feel how he feels even though he sounds like a jealous baby.

As Amy and Sheldon realize that they make more progress when they are insulting each other, they decide to eliminate the ground rules. Their conflicts together really help them make progress which thrills both of them.

Leonard starts to tell Raj and Penny that he's been feeling left out lately and then gets left out of their discussion of the subject. When they ask him what he wants to say, Leonard admits that Raj and Penny pretty much covered it.

Meanwhile, Sheldon and Amy make up new ground rules which encourage competition and antagonism in the name of scientific progress.



  • Title Reference: Refers to Sheldon and Amy working together and how they "fluctuate" between working and insulting each other.
  • Music: "Happy Together (song)|Happy Together" by The Turtles|the Turtles.
  • Taping date: March 7, 2017
  • This episode was watched by 12.78 million people with a rating of 2.6 (adults 18–49).
  • Total viewers including DVR users 17.18 million.
  • This episode aired in Canada on March 30, 2017.
  • Chuck Lorre's vanity card. [1]
  • Episode transcript [2]


  • Caroline Preece at Den of Geek! - Very little is most likely just enough for the majority of the show's viewers, but there are others who'll always demand more. That's been the problem with Leonard and Penny this season - the writers have cycled through everything they had planned for the male and female lead, and there's nothing left. They're left with scraps while the better writing goes towards Sheldon and sometimes Howard. Which is why having Raj move into the main apartment was a great idea. It's not going to set anybody's world on fire, but it's a fun change of dynamic that solves two of The Big Bang Theory's major issues. It gives them an excuse to write a A-plot involving Penny and Leonard, and it puts Raj front and center. [3] IMDb user reviews


  • Raj and Penny start to bond over common interests.
  • Sheldon and Amy begin working on a science project together.
  • This episode was the closest to a moment where Leonard or Bernadette would be having a conversation in a nice, sweet and, to some degree, helpful way with the other. The last episode where someone spoke nicely to the other was in the final scene of "The Deception Verification" (S7E2) where Bernadette tells Leonard in a sweet voice and smiling that Raj was able to talk in front of the girls without a beer right after Leonard left for his expedition to the North Sea.


[first lines]

Raj: So, Downward Facing Dog comes from the Sanskrit phrase Adho Mukha Svanasana.
Penny: Oh, that's beautiful. What does it mean?
Raj: Downward facing dog.
Penny: Yeah, I guess they don't have Sanskrit for butts up and heads down.
Raj: Hey, we wrote the Kama Sutra; if it involves butts there's a word for it.

[last lines]

Sheldon: Can you read them back?
Amy: Revised ground rule number one: we are on the same team but it *is* a competition.
Sheldon: Excellent, excellent. And on a related point, you're going down, punk.
Amy: Revised ground rule number two: there are definitely stupid questions, and those who ask them can be told so right to their *stupid* face.
Sheldon: I love that one.
Amy: Thanks, babe. Number three: fair topics for insult include educational pedigree, scientific field, intellectual prowess, and mommas.
Sheldon: That list is *strong*. Like your mother's urge to be promiscuous with sailors.

Sheldon: I believe I've made some progress on our ground rules.
Amy: Oh, good. What are they?
Sheldon: Number one: in matters of physics, I have the final say. In matters of neuroscience, you have the final say, unless I disagree. Number two: when we publish, my name goes first. Oh, subsequently, if we win any awards, I speak first. I don't want to be talking when the orchestra plays us off.
Amy: Can I see that?
Sheldon: Of course. [Amy takes notebook and tosses it out the window]
Sheldon: I'll get that back. Like all my underwear, that notebook says "Property of Sheldon Cooper".
Amy: Sheldon, if we're gonna have ground rules, I'll tell you the first ground rule: I make the ground rules.
Sheldon: I'd write that down, but I can't, now can I?

Amy: We're finally making progress. I wish we could do it without fighting.
Sheldon: What if the fighting is the reason we're making progress?
Amy: I suppose it's conceivable that the hormones associated with our fight or flight response could be sharpening our cognitive processes.

Amy: I had a feeling you were using the wrong computational model, but I didn't say anything 'cause you're so sensitive!
Sheldon: Just because I'm easily bothered by light, heat, sound, smell and the way birds look at me does not mean I'm sensitive!

Sheldon: Gentlemen, the most interesting thing just happened with this spoon.
Howard: Unless it was singing "Be Our Guest", I doubt it.

Amy: [Looking at their boards] Wow. Look at that.
Sheldon: Yes. It's remarkable.
Amy: So we're agreed: it's total garbage.
Sheldon: By the way, your name can go first.

Amy: [after carrying her harp up the stairs] You know, I like harp lessons, but I'm thinking of switching to elevator repair lessons.

Sheldon: Can you stop breathing so loud? I can hear your nose whistling.
Amy: I can hear your face talking, so we're even. [Beat]
Sheldon: All right! Either blow your nose or teach it to play Camptown Races!
Amy: FIne! Fine! You want me to blow my nose? Here, I'll blow it! [Blows nose really hard at Sheldon]
Amy: Better?
Sheldon: No, I can still hear it. Oh, wait, that's me. Never mind, it's fine.