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"The Cohabitation Experimentation" is the fourth episode of the tenth season of the American sitcom The Big Bang Theory. The episode aired on Monday, October 10, 2016.


When Amy's Apartment is flooded, Leonard and Penny invite her to stay with them. Then Amy proposes to Sheldon that they live together as an experiment. Howard and Bernadette wonder about wanting to know the gender of their baby. Unfortunately Raj knows.

Extended Plot[]

Amy, Leonard and Penny enter the lobby with that night's take-out food as Amy describes the plumbing problem in her apartment. A pipe broke over her clothes closet destroying all her clothes and her apartment will be uninhabitable for five weeks. Penny suggests that she stay in Leonard's bedroom while the Hofstadters stay across the hall. Technically Amy would be moving in with her boyfriend while Penny gets to live "alone" with her husband. A big step in the right direction for both of them. The trio enter apartment 4A and stare at Sheldon who is at his desk. Sheldon then asks them why they were standing there smiling like crazy people.


Three that are happy about Shamy moving in together.

While setting up dinner, Sheldon comments that cohabitation is a lot to process. Penny reminds him that it is only for five weeks and that they'll be right across the hall. Sheldon is worried that it could kill the romance especially since she will see him unshaven. Leonard reminds him that if he shaves now, he is good for three months, with Penny adding that their romance can't be killed since they only had sex once. Amy proposes it to him as a scientist to collect data about their compatibility. Sheldon considers her luring him in with some "sexy talk". Like Star Trek, Leonard compares it to Sheldon's own five-week mission. Now that is what Sheldon considers as sexy talk. Next, Sheldon is worried that he might find it uncomfortable with Amy because he wasn't gonna be in a familiar environment, they need a neutral ground, Penny tells them to move in across the hall, Sheldon is worried about his knocking and spot privileges, Leonard tells Penny to keep nodding since he is almost out of the apartment. Finally Sheldon accepts the five-week mission as Amy grabs and hugs him happily.

Howard, Bernadette and Raj enter the kitchen as Raj tells them how happy he is with their OB/GYN. Howard complains that he doesn't have to come to every appointment. Raj reminds them that he is the son of a gynecologist. Bernadette does not like him describing her textbook cervix. The parents look lovingly at the blob on the sonogram photograph and jokingly call the baby Blobert, Bloberta or Blobbi. Then they consider whether to call back the doctor to find out the baby's gender. Raj casually says that he knows what it is, horrifying Howard and Bernadette, as they don't want him to know at all.


Discussing whether to find out the gender of their baby.

Sheldon and Penny are sharing a drink in apartment 4B with Penny telling Sheldon how proud she is of his decision. Sheldon explains that the experiment would be better if there were four pairs of Amy's and Sheldon's. Sheldon then asks Penny for advice about living together and Penny tells him to be willing to compromise, do little things for her and respect Amy's space. Amy is seeking advice from Leonard who wants to frame it so that she won't want to stop thinking about it. She can't leave any belts on the floor (They look like snakes), keep M&M's in her pocket for long waits in lines and no photoflash photography.

Sheldon is packing his underwear as Amy wants to discuss the sleeping arrangements. Sheldon is excited, concerned and scared, just like when he goes on Space Mountain. Amy realizes on the subject of coital expectations, she knows that he is way out of his comfort zone. She proposes that they take sex off the table until they get more comfortable living together. Sheldon agrees. Their discussion was getting him all worked up and he was about to kiss her. Amy had the same feeling having seen his Teen Titans underwear.


Here is your key.

In the hallway, Sheldon has his clothes in a laundry basket and Amy has her suitcase as Penny gives them the keys to their apartment. Penny tells them to enjoy their new place, while Leonard tells Sheldon to enjoy his mission to go boldly where no one has gone before. Sheldon remarks that since it's Penny's bedroom, many men have gone there before. Amy is ready to go while Sheldon keeps giving Leonard chore reminders (one of which he wrote on Penny's right palm). They say their final farewells and then Sheldon and Amy are in the apartment alone officially living together. Sheldon declares that the experiment has began. Penny and Leonard can be heard yelling, "WE DID IT!"

Later, while Amy is unpacking, Sheldon wonders which side of the bed she wants. Since Sheldon is more fuzzy about things, she wants him to pick one. They argue about who should pick and Amy insists that Sheldon do it. The left is closer to the door for exit in case of emergency, but is closer to the entrance in case of attack. The other side is closer to the window, but perverts could be watching him while he slept. Amy then closed the drapes as a solution. That solves the problem until Sheldon wonders about someone standing behind the drapes.

Howard is coming to bed while Bernadette remarks that it is ridiculous that everyone else knows the sex of the baby including the doctor, the sonogram technician, Raj and maybe even his entire "Gray's Anatomy" chat room. Howard thinks that it will be more fun like a magic trick. Like the never-ending hanky that he pulled out of his fly which ended in a flower bouquet for her, the doctor will pull something beautiful out of her. Bernadette quips that she should've listened when everyone said she could do better than Howard.


Penny wants to know what Leonard would like to do now that Sheldon's gone.

Amy is getting ready for bed, making noises from the bathroom. Sheldon makes a sour face from those noises and then moves over to the side of the bed away from the bathroom. Amy notices his move and Sheldon remarks that she should be glad he was still in the room. Amy climbs in and then asks that since sex if off the table, can they snuggle? Sheldon wants to build a wall of pillows between them. Amy shoots his idea down. Sheldon says that he is very sensitive to heat and that her bottom should have iguanas lying next to it. Amy looks shocked as Sheldon turns over to go to sleep.


Penny dancing up a storm since they now live alone.

Over to Apartment 4A, Leonard looks at his wristwatch declaring that it is Sheldon's bedtime and he is in for the night. Penny is ecstatic to have the apartment all to themselves and asks what he wants to do and he takes his jacket off. She says he's a genius and that that's the best he can suggest. Leonard replies that since Sheldon is not there, they are going to put on some music and dance in their underwear. Penny just wants to have sex. Leonard tells her that that is inevitable after she sees him dancing. She does not looked convinced as he pulls down his pants and gets rocking.

Howard throws down a magazine and says that he is calling Raj which excites Bernadette. Then Bernadette has second thoughts. Raj is asleep with Cinnamon and picks up the phone just as Howard hangs up.

Penny eventually caved in and is seen dancing with Leonard.

Sheldon is now snoring and Amy can't get any sleep.

Next Penny is comforting Leonard who exerted himself from doing the worm and is now on his asthma inhaler.

Raj gets another call and hears Bernadette shouting to hang up.

Amy is now spooning with Sheldon looking very happy. Sheldon keeps moving toward her side of the bed and then pushes her onto the floor. Sheldon wakes up and wonders what she is doing on the floor. Amy takes out her phone, takes a flash picture on him and he runs away.


Amy happily snuggling up with her man.

Next morning Amy and Penny are having coffee and everyone's tired. Amy complains that she got very little sleep. Penny smiles at her and told her to "Yeah, get it, girl". Amy says that it's not what she thinks. Leonard joins them complaining about he pulled muscle|pulled something. Penny quips that it's really not what Amy thinks. Sheldon enters (without knocking) telling them about his good night's sleep. Amy sighs that she was on the floor all night and that maybe living together was a bad idea. Sheldon argues that she is a scientist and should stick with the experiment. Then he questions her integrity as a scientist. She replies that a theoretical scientist like him wouldn't even understand the experiment variables. Then they agree that for science they should continue the experiment. Amy then suggests that they return to their apartment and make out which is fine for Sheldon. Their argument about science turned each other on. Penny jokingly comments on how their "new neighbors" are weird.



  • Title Reference: Sheldon and Amy agree to an experiment in living together.
  • Taping date: September 13, 2016
  • This episode was watched by 14.41 million people with a rating of 3.4 (adults 18–49).
  • Total viewers including DVR users 19.69 million.
  • The Big Bang Theory was ranked #1 for the week ending 16 October 2016.
  • This episode aired in Canada on October 10, 2016.
  • Chuck Lorre's vanity card [1].
  • Episode transcript [2]


  • Uve in The Daily Fandom - Sheldon and Amy obviously encounter some problems while living together, if only for comedy's sake, but then they also fix it with make out sessions, like any other couple. Right now, what I wish for the most is that, since Amy's supposed to have this problem for a few weeks, this situation will last for a few episodes. Having the four of them living in the same building a la FRIENDS will certainly open up many new possibilities for funny situations. [3]
  • IMDb user reviews [4]


  • Music: "You Can Never Tell" by Chuck Berry; "Tootsee Roll" by 69 Boyz
  • Sheldon and Amy step up their relationship when Amy gets Sheldon to agree to an experiment at living together (no sex initially) after her apartment has a plumbing problem.
  • Penny and Leonard are excited that they are finally living "alone" - Sheldon-free.
  • As of this episode, both Lenny and Shamy are now officially living together, after the disastrous attempt in "The Spoiler Alert Segmentation".
  • Cinnamon makes an appearance sleeping with Raj for the first time since "The Locomotive Manipulation" (S7E15).
  • First time the window in Penny's old bedroom is ever seen.
  • Talking about or arguing about science really turns Amy and Sheldon on.
  • Goofus and Gallant were the bad and good manners twin boys in a "Highlights for Children" magazine comic strip.
  • Sheldon likes to have his coitus with minimum or no foreplay.
  • Howard and Bernadette's remodeled bedroom is seen for the first time.
  • Shamy is living together despite Sheldon's strict Christian upbringing that he doesn't really believe in.


Amy: There was water everywhere. It was such a mess.
Leonard: That stinks. How long are you out of the apartment?
Amy: About five weeks.
Penny: Ugh, did you lose anything valuable.
Amy: Well, the pipe was over my closet so all my clothes are gone.
Penny: Oh, so nothing. Great. Do they know what caused it?
Amy: They didn’t say.
Leonard: Buildings that have a combination of copper and galvanized steel are susceptible to pinholes and corrosion caused by the mobility of ions in water. [Women glare at him.] Can’t have your head shoved in a toilet as much as I did and not pick up a few things about plumbing.
Penny: Well, if you need a place to crash, you can stay with us.
Amy: Really?
Penny: Of course. You can stay in Leonard’s room and we’ll stay at my place.
Amy: You sure that’s not an inconvenience?
Penny: No. Not at all.
Leonard: And we live with Sheldon, so the word “inconvenience” has really lost all meaning.
Amy: So technically I’d be moving in with my boyfriend?
Penny: I guess so. I’d finally get to live alone with my husband.
Amy: Oh my, this is a big step.
Leonard: Yeah. For the two of us, it’s a step in the right direction.
Sheldon: [Everyone is grinning at Sheldon] Why are you all smiling like crazy people?

Sheldon: Cohabitation with my girlfriend? That’s a great deal to process. Hmm.
Penny: It’s only for five weeks. And we’ll be right across the hall.
Amy: What do you think?
Sheldon: I don’t know. What if living together kills the romance?
Penny: Okay, you guys only had sex only one whole time. Nothing can put a fire out like that.
Sheldon: Yeah, but what happens when he get a peek behind the curtain? I mean, she has never seen me unshaven.
Leonard: You just shaved yesterday. You’re good for three months.
Amy: Sheldon, I understand your apprehension, but let me appeal to the scientist in you. Given the five-week end date, isn’t this the perfect opportunity consider this an experiment and collect data on our compatibility?
Sheldon: Don’t try luring me in with “sexy talk”.
Leonard: Okay. Star Trek: the Original series. The Enterprise was on a five-year mission to explore new worlds. Think of this as your own personal five-week mission to do the same.
Sheldon: If you want to lure me in with “sexy talk”, that’s how you do it.
(Leonard smiles)
Penny: Don’t be that proud of that.
Amy: So is that a yes?
Sheldon: Not yet I…How will I learn if I’m comfortable with Amy or just comfortable because I’m in my own apartment? Now if this experiment is going to be valid, I suggest a neutral environment.
Penny: Well, where would you go?
Sheldon: Well, ideally an enclosed self-sustaining biodome in New Mexico. Where we would eat crops fertilized by our own wastes.
Leonard: And you were worried about the romance!
Penny: Wait. Why don’t you guys stay across the hall, and we live here?
Sheldon: Interesting. If my official residence is the hall, I wonder if I need to knock every time come over here?
Leonard: That’s a good question. Maybe just don’t come over.
Sheldon: Historically I don’t do well with change.
Penny: Okay, it won’t be that bad. We wouldn’t even sit in your spot while you’re gone.
Sheldon: You’re darn right, you won’t. No matter where I am this will always be my spot. Like an embassy in a foreign country, this seat is the sovereign soil of my bottom.
Leonard: Just nod and smile. He’s almost gone.
Amy: Sheldon, what do you think?
Sheldon: [Sighs.] Very well, I’m on board.
Amy: Seriously?
Sheldon: Yes. I accept the five-week mission to share a living space with my girlfriend.
Amy: Oh, this is so exciting! [Amy hugs Sheldon.]
Sheldon: Well, now don’t be surprised, if like Star Trek, it is cancelled in three.

Bernadette: It would help if you would stop telling me that I have a textbook cervix.

Amy: You and I are going to be sharing a bed. You know, this is uncharted territory for both of us. How are you feeling about that?
Sheldon: Oh, excited, concerned, a little scared. All the small emotions I feel in the line at Space Mountain.
Amy: Well if you’re nervous about the sleeping arrangements, maybe we should talk about it.
Sheldon: Okay. Talk.
Amy: Well, I imagine one of your concerns might be coital expectations.
Sheldon: No foreplay or anything, just get right to it.
Amy: Look, I know this experiment is a big step outside of your comfort zone. So why don’t we take being physical off the table and maybe later once we’re more settled in it we can revisit it.
Sheldon: You’ll really okay with that?
Amy: I’ve never lived with anyone, either. This is a lot for me, too.
Sheldon: [sighs.] This is such a relief. Honestly, if it didn’t get you all worked up, I’d kiss you right now.
Amy: Good call. Seeing your Teen Titans underwear really got my motor running.
Sheldon: I know. They probably shouldn’t sell those to children.

Amy: Well, that’s it. For the next five-weeks we are officially living together.
Sheldon: I guess the experiment begin.
Penny: [Through the door.] We did it!
Leonard: [Through the door.] Yeah!

Sheldon: Which side of the bed would you prefer?
Amy: Doesn’t matter to me. Your choice.
Sheldon: No, no. We’re living together now. Everything’s equal. You know. I have a tendency to be controlling so I’d rather have you choose.
Amy: Well, Sheldon, I really appreciate that, but these things mean more to you so whatever you want.
Sheldon: Well, clearly it’s not whatever I want for what I want is for you to make this decision and you refuse to do that.
Amy: I am not refusing. I’m just trying to be considerate.
Sheldon: Like the time you got me those shoes with the wheels on the bottom then you watched me roll into traffic.
Amy: Sheldon, would you please pick a side.
Sheldon: Fine. [Sighs.] Okay on this side I am closer to the exit in case of emergency.
Amy: Great. That will be your side.
Sheldon: No, but know I am also closer to the entrance in case of attack.
Amy: Okay, I’ll take that side.
Sheldon: And again then the odds of somebody attacking me?
Amy: Rising rapidly.
Sheldon: Now this side offers me proximity to the bathroom, but I am closer to the window where perverts can watch me sleep.
Amy: Okay. What if we do this? [Closes drapes.]
Sheldon: I suppose that works.
Amy: Great.
Sheldon: Although, now I’m worried someone is hiding behind the drapes.

Sheldon: Okay, well, I’m sorry. I’m just worried about my sensitivity to temperature could make this a rough night. And no offense, but your bottom radiates enough heat, I’m surprised there are not iguanas lying on it.

Amy: I’m so sore. I don’t think I slept two minutes last night.
Penny: (smiles) Yeah! Get it, girl.
Amy: It’s not what you think.
Leonard: I feel like I pulled something. Why didn’t you tell me to stop?
Penny: Even more not what you think.
Amy: I don’t think I can make though five weeks of living with him.
Leonard: If you ever need a break, the owner of the train store will you let you leave him there while you get coffee.
Penny: Yeah.
Sheldon: Good morning, everybody. See. I didn’t knock, but its fine. I didn’t knock, but its fine. I didn’t knock, but its fine. So, how is everyone?
Amy: Miserable and exhausted.
Sheldon: Really? I slept great.
Amy: Well, I didn’t and it’s your fault.
Sheldon: How? You had the whole floor to yourself.
Amy: Maybe living together is a bad idea.
Sheldon: Well, yeah. But what kind of scientists would we be drawing a conclusion after only 12 hours of data.
Amy: The kind that almost put a pillow over your face last night.
Sheldon: Wow. I anticipated that we’d have problems, but I never thought your scientific rigor would be one of them.
Amy: I’m sorry, are you questioning my integrity as a scientist?
Sheldon: If the lab room disposable cover fits.
Penny: Was that a science diss?
Leonard: Yeah.
Penny: Was it a good one?
Leonard: Eh.
Penny: Ah.
Amy: What would a theoretical physicist understand an experiment anyway? I mean, you wouldn’t even know a confounding variable if two of them hit you in the face at the same time. And you don’t even get that joke because you don’t work with confounding variables.
Sheldon: How dare you!
Amy: Oh, you heard me. Your experimental bona fides are laughable.
Sheldon: Whoa, whoa. Now you’re making fun of my bona fides!
Amy: Can’t make fun of a null set.
Penny: I feel like I should say “Damn”.
Leonard: Do it.
Penny: Damn!
Sheldon: Well, if you’re so protective of the scientific method, perhaps we should see the next five weeks through to finish what we started.
Amy: Well, for science, maybe I will.
Sheldon: For science, maybe you should.
Amy: Fine.
Sheldon: Fine.
Amy: Good.
Sheldon: Great.
Amy: Do you want to go to our place and make out?
Sheldon: Does Stephen Hawking roll though the quad? [They leave.]
Penny: The new neighbors are weird.