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"The Gorilla Experiment" is the tenth episode of the third season of the American sitcom The Big Bang Theory. This episode first aired on Monday, December 7, 2009.


Sheldon attempts to help Penny understand physics to impress Leonard, and Howard becomes jealous when his girlfriend Bernadette takes an interest in Leonard's research.

Extended Plot[]

The Gorilla Experiment 02

Howard introducing his new girlfriend, Bernadette.

Bernadette Rostenkowski is joining the gang for takeout around the coffee table making Sheldon unhappy. First there is only enough food for five people and not six and Bernadette tries to sit in Sheldon's Spot. After Bernadette, asks what is so special about that spot on the couch, Penny goes through Sheldon's standard explanation about temperature, air currents and the position of the television. Sheldon is impressed and tells Penny that there is hope for her yet which pleases her. Penny likes the addition of Bernadette since she can have girl talk about things like shoes which is the definition of Hell for Sheldon. Bernadette is always laughing at Howard's jokes because his face lights up when she laughs. (Penny: "Howard, don't ever let her go."). She is also interested in Leonard's experiments though Sheldon finds them as ground-breaking as 3rd graders growing lima beans on wet paper towels. Penny feels lost as Bernadette shows a huge interest in physics.

Raj playing as Yoshi defeats Sheldon playing as Mario in Mario Kart, then Penny comes over asks him for a favour and Sheldon tells Raj to leave. She wants him to teach her a little physics so that she can understand Leonard's work and surprise him. ("If you really want to surprise him, why don't you do something like clean your apartment?") Penny suggests that it would make for a fascinating experiment. Sheldon compares it to teaching Koko the Gorilla sign language.

Howard brings Bernadette in to show her his work and to show everyone that he has a girlfriend. Leonard invites her to his lab to look at some of his experiments. After she leaves, Howard accuses Leonard of moving in on his girl. (It's not enough you got the Prom Queen, now you want the Chair of the Decorating Committee?)

Penny shows up for her lessons on time, well-rested, and eager to learn as Sheldon notes. ("Apparently, ignorance is bliss.") After giving her a notebook, he begins his lecture back in ancient Greece, where people would look up at the stars and see some of them move in the night sky. They are going to embark on a 2600-year journey from the Greeks to Isaac Newton to Niels Bohr to Erwin Schrödinger to the Dutch researchers Leonard is currently ripping off. Penny leaves for the bathroom first and Sheldon notes: Project Gorilla - Entry 2. I'm exhausted!

Howard and Bernadette are fooling around up in his room and are interrupted by his mother. He sends her off to the grocery after asking for her to cook lamb stew for dinner. Leonard texts Bernadette to tell her that Howard might not like it if she went to his experiment tomorrow. Howard doesn't and Bernadette is not happy that Howard wants to control whom she is friends with.

Sheldon is trying to teach Penny physics, but she doesn't understand anything and starts to cry because she thinks she is stupid. Sheldon doesn't think that that's no reason to cry. One cries when one is sad. He cries because others are stupid and that makes him sad. Penny just wants to know what Leonard does. He works with subatomic particles. Penny then asks what they are. Sheldon considers that a good questions and to answer that he starts his whole lecture over again. Penny reacts with “Oh balls!”

Howard goes to Leonard's lab mad that Leonard text-blocked him with his message to Bernadette. He doesn't want to look like a petty, jealous douche though he admits that he is. When Bernadette arrives, he says that he was interested in Leonard's experiment as well though he told Bernadette that he thought it was stupid. He apologizes to Bernadette for what he did, though Leonard gets back at him by putting her name for him, "Tushy-face", on Twitter.

At the next dinner, Penny comments on Leonard's work using a complicated analysis that surprises everyone reiterating Sheldon's usual condescending remarks about Leonard's work. Sheldon nods approvingly. Then she also wants everybody to know that Fig Newtons were named after a town in Massachusetts and not the scientist which has everyone know that Penny hadn't changed.



  • "Another typical episode. All the pieces are on the board yet the producers refuse to deploy them correctly. The focus of this episode as ever is Sheldon. And he is, but that isn't the point of this story. Penny feels insecure because she can’t talk to Leonard about his work and Howard is insecure about losing his girlfriend. That should be the focus. It’s not that complicated...But once more the issue of Leonard and Penny’s relationship was ignored. Her insecurity and desire to learn some physics is a nice idea. It points to her affection for him but we don’t see it often enough...In the end she actually learned some physics talk which put down Leonard’s work. She actually insulted him which was completely counterproductive as it made her look either foolish or mean." - The TV Critic's Review


  • Title Reference: Penny's suggestion that Sheldon should treat teaching her physics as an experiment. Sheldon subsequently names the experiment "Project Gorilla," after Koko the gorilla who learned sign language.
  • Chuck Lorre's vanity card [1]
  • This episode was watched by 14.38 million people with a rating of 5.6 (adults 18–49).
  • This episode aired in Canada on December 7, 2009.
  • Episode transcript [2]

Costume Notes[]

The Gorilla Experiment 14 - Geometry


The Gorilla Experiment 16 - Red Blue Unknown


The Gorilla Experiment 12 Bat Buckle

Bat Buckle

The Gorilla Experiment 11

Atmospheric CO2

The Gorilla Experiment 17 - RedUnknown


The Gorilla Experiment 18 - TVTest2

TV Test

The Gorilla Experiment 15 - Phone Buckle

Phone buckle

The Gorilla Experiment 13 Brown Sound

Brown Sound Fly Lower

The Gorilla Experiment 19 - Violet Lantern

Violet Lantern


Set Notes[]

New in Howard's bedroom:

The Gorilla Experiment 09 - HowardRobotClock

Robot Clock


  • Sheldon objects to the saying 'the more the merrier' in this episode; however, in "The Codpiece Topology" (S2E2), he is using this saying.
  • The Technical Consultant David Saltzberg appears in this episode. He was the first person on the left that Howard passed when he entered the dining room introducing Bernadette as his girlfriend to everyone. (Look for the guy in the brown sweater vest at the first table).
  • The answer to the question Penny couldn't answer was F = Ma = Mg.
  • Raj and Sheldon were playing Mario Kart Wii on the Wii, with Raj playing as Yoshi and Sheldon playing as Mario on the Mario Circuit stage.
    • After Sheldon mentions how he lost because he got stuck behind a tree, Raj mentions how he also got stuck behind a cow and a penguin, likely referencing the stages Moo Moo Meadows and N64 Sherbet Land, which respectively feature those animals as hazards..
  • This is the third episode to feature the Wii.
  • Penny's (apparently fed by Sheldon and then memorized) monologue at the end of the episode is highly technical, but essentially means that "your experiment is unnecessary, as the important results were already known (discovered by a Dutch team)".
  • This may refer to the paper "Magneto-electric Aharonov-Bohm effect in metal rings", published in 1998 and indeed performed by Dutch researchers (Alexander van Oudenaarden, Michel H. Devoret, Yu. V. Nazarov, and J. E. Mooij; Nature, February 1998, doi:10.1038/35808).
  • Since "The Lizard-Spock Expansion" (S2E8), Sheldon now understands the phrase "oh snap."
  • Howard says he practically invented using fancy lab equipment to seduce women. An example of Howard using this technique is letting Stephanie Barnett drive with the Mars rover in "The Lizard-Spock Expansion"-S2E8 (into a ditch, no less).
  • After the text message from Leonard one can see a picture of "Mirror's Edge".
  • In "The Bath Item Gift Hypothesis" (S2E11) Leonard also mentions the gorilla that learned sign language described by Sheldon in this episode.
  • Sheldon compares Penny to a sign language gorilla. In the seventh season, Penny plays a gorilla/girl clone in her movie Serial Ape-ist 2: Monkey See, Monkey Kill.
  • In this episode Sheldon sarcastically quips about an eating contest with his hands behind his back, which he later had in "The Re-Entry Minimization" (S6E4).
  • First time Bernadette is in Leonard and Sheldon's apartment. Howard introduces her as his girlfriend.
  • Sheldon mentions his mother in the apartment dinner scene whilst Bernadette and Penny finish their girly chat about shoes. Sheldon's mother does not appear in this episode. By this point, Bernadette still doesn't meet Sheldon's mother in three later season episodes that Sheldon's mother did appear in (1: S4E3, 2: S5E6 and 3: S8E23). Also, Laurie Metcalf was not available to have a guest appearance in this episode.


(The bedroom scene at the Wolowitz household of Howard smooching with Bernadette on his bed for a five seconds whilst Howard tries to get to her big black bra underneath her blouse and they both keep smooching for a few more seconds)
Bernadette: Howard?
Howard: (in between smooches) Huh?
Bernadette: It unhooks in the front.
Howard: (giggling) Oh, that explains a lot.
Howard’s Mother (off): Howard, I’m home!
Howard: Of course.
Howard’s Mother (off): Senior fitness was cancelled. It turns out you can forget how to ride a bike. I’m fine, but, oy, did Sam Harpootian eat gravel.
Howard: That’s great, Ma!
Bernadette: I guess I should go.
Howard: No, no, don’t move. (shouts loudly to his mom) Hey, Ma, can I have lamb stew for dinner?
Howard’s Mother (off): Lamb stew? I’d have to go to the supermarket.
Howard: Please? I got a real hankering.
Howard’s Mother (off): Oh, I can’t say no to my little tushy face. I’ll be back soon.
Howard: Thanks, Ma.
Howard’s Mother (off): Do you want the regular peas or the Le Seur?
Howard: Always Le Seur peas with lamb stew!
Howard’s Mother (off): You’re right! When you’re right, you’re right! What if they’re out of the Le Seur?
Howard: Then get the regular!
Howard’s Mother (off): All right! You don’t have to yell!
Howard: (quietly to Bernadette) Sorry about that.
Bernadette: (her phone chimes) Let me just put that on vibrate.
Howard: I’m already on vibrate.
Bernadette: You know, that one I got. (she looks downs at the text message and she asks Howard crossly) Howard, did you say something to Leonard about me?
Howard: Uh, what do you mean?
Bernadette: He says if I go see his experiment tomorrow it might weird you out.
Howard: Really? He said that?
Bernadette: You’re not jealous of Leonard, are you?
Howard: Me? No. I may have mentioned that it’s a little inappropriate to be asking another man’s girlfriend to his experiment without first discussing it with said man.
Bernadette: Are you saying I need to ask your permission to hang out with Leonard?
Howard: I didn’t say anything like that. I said Leonard has to ask my permission.
(Scene at the front door of Mrs. Wolowitz's house where Bernadette storms out in such fury)
Howard: (he yelling after Bernadette) Come on, I don’t want to eat lamb stew with my mother. (He is seeing that Bernadette has now gone off in a rage. He now yells loudly at himself) Damn, I was this close on the bra.
(Howard now goes back into his mom's house)

Sheldon Cooper: Why are you crying?
Penny: Because I'm stupid!
Sheldon Cooper: That's no reason to cry. One cries because one is sad. For example, I cry because others are stupid, and it makes me sad.

Penny: Hey, Leonard, check this out. (Throws some food in the air and catches it in her mouth)
Sheldon: Leonard, she’s doing it again.
Leonard: I think it upsets Sheldon when you play with the food.
Sheldon: No. It upsets Sheldon when she willy-nilly takes it from the containers without regard for its equitable distribution. This is essentially why you have famine in India.
Penny: You want me to put it back?
Sheldon: Leonard.
Leonard: It upsets Sheldon when you play with the Sheldon.
Howard: (arriving) What’s up, my nerdizzles? Raj, Sheldon, I want you to meet my girlfriend Bernadette.
Sheldon: Hello.
Howard: Leonard, Penny, you know my girlfriend Bernadette.
Leonard: Yeah. Hey.
Howard: Bernadette, say fo’shizzle to my nerdizzles.
Bernadette: I don’t think I can. I don’t have Howard’s street cred.
Howard: I hope it’s all right, I told my girlfriend Bernadette she could join us for dinner.
Leonard: Sure. The more, the merrier.
Sheldon: Wait, no, that’s a false equivalency. More does not equal merry. If there were 2,000 people in this apartment right now, would we be celebrating? No, we’d be suffocating.
Leonard: Sheldon…
Sheldon: Don’t Sheldon me. We ordered for five people, not six.
Penny: Oh, come on, it’s fine. We’ll just put it all on the table, you know, family style.
Sheldon: Oh, sure. And while we’re at it, why don’t we put our hands behind our backs, have an old-fashioned eating contest?
Leonard: Relax, it'll be fine. Sit down, you guys.
[Everyone says no as Bernadette goes for Sheldon's spot]
Bernadette: What? no
Penny: Oh, yeah. You can't sit there.
Bernadette: Why not?
Leonard: That's where Sheldon sits.
Bernadette: He can't sit somewhere else?
Penny: Oh, no, no. You see, in the winter that seat is close enough to the radiator so that he's warm yet not so close that he sweats. In the summer, it's directly in the path of the cross breeze created by opening windows there and there. It faces the television on an angle that isn't direct so that he can still talk to everybody, yet not so wide that the picture looks distorted.
Sheldon: Perhaps there's hope for you after all.

Bernadette: Ooh, I love your shoes.
Penny: Oh, thanks. They are cute, aren’t they?
Bernadette: Where’d you get them?
Penny: Shoes for Less.
Bernadette: I’ve been meaning to go over there.
Penny: Oh, great selection, great prices.
Sheldon: My mother was right. Hell is real.
Howard: Come on, Sheldon. let the womenfolk chat.
Penny: Womenfolk?
Howard: Gals? Chicks? Utero-Americans?
Penny: Just eat your dinner.
Bernadette: Don’t take him too seriously, a lot of what he says is intended as humour.
Penny: Yeah, well, I don’t think it’s very funny.
Bernadette: Me neither, but he just lights up when I laugh.
Penny: Howard, never let her go.
Bernadette: So, Leonard, Howard says you’re working on fundamental tests of quantum mechanics.
Leonard: I am. Are you interested in physics?
Bernadette: Oh, I find it fascinating. If I hadn’t gone into microbiology, I probably would have gone into physics. Or ice dancing.
Leonard: Actually, my tests of the Aharonov-Bohm quantum interference effect have reached an interesting point. Right now, we’re testing the phase shift due to an electric potential.
Bernadette: That’s amazing.
Sheldon: Yes. Leonard’s work is nearly as amazing as third graders growing lima beans in wet paper towels. (Raj whispers to him) While I appreciate the oh, snap, I’m uncomfortable having your moist breath in my ear.
Bernadette: Are you going to try to set up the voltages using tunnel junctions?
Leonard: Yes, I am. You want to see a simulation on my laptop?
Bernadette: Oh, yeah, show me. In microbiology, the most exciting thing I get to work with is yeast.
Sheldon: Howard?
Howard: Yeah?
Sheldon: Your shoes are delightful. Where did you get them?
Howard: What?
Sheldon: Bazinga. I don’t care.

Sheldon Cooper: This is just the beginning of a 2600 year journey, from the ancient Greeks, to Isaac Newton, to Niels Bohr, to Erwin Schroedinger, to the Dutch researchers Leonard is currently ripping off.

Sheldon Cooper: And all of that tells us that...?
Penny: That Newton was a really smart cookie? Is that why they call them Fig Newtons?
Sheldon Cooper: No, Fig Newtons are named after a small town in Massachusetts - No, don't write that down!

Leonard Hofstadter: Most people aren't that interested in what I do.
[Penny and Sheldon look at each other knowingly]
Penny: Actually, that's not true, Leonard. Recently, I've been thinking that, given the parameters of your experiment, the transport of electrons through the aperture of the nano-fabricated metal rings is qualitatively no different than the experiment already conducted in the Netherlands.
[Everyone stares at Penny in disbelief]
Penny: Their observed phase shift in the diffusing electrons inside the metal ring already conclusively demonstrated the electric analogue of the Aharonov-Bohm quantum-interference effect.

(The scene in Leonard's lab where Howard storms up to Leonard with a face like thunder)
Howard: (he is really angry) Okay, I got a bone to pick with you.
Leonard: What did I do now?
Howard: (aggressively) I was in bed with Bernadette, and you text-blocked me.
Leonard: What?
Howard: (he's even more aggressive) We were completely naked, about to devour each other when, (he imitates a couple of texting sounds) you text her that I have a problem with her hanging out with you.
Leonard: (argues with Howard) You do have a problem with her hanging out with me.
Howard: (argues back with such loud anger) Yeah, but that’s not what you tell her.
Leonard: (argues with Howard again) What was I supposed to tell her?
Howard: (argues back with such loud anger again) I don’t know, something that doesn’t make me come off as a petty, jealous douche.
Leonard: And what would that be?
Howard: Come on, do I have to think of everything?
Bernadette: Hey, Leonard. Am I too late to see the experiment? (she sees Howard for a second and she now gets cross) Oh, hi.
Howard: Hi.
Bernadette: (she's asking Howard crossly) What are you doing here?
Howard: Same thing you’re doing here. I came to see Leonard’s experiment.
Bernadette: (she's a tiny bit angry) No, you didn’t. You said Leonard’s experiment was stupid.
Leonard: You told her my experiment was stupid?
Howard: I was just repeating what Sheldon said. Let’s not get off topic, Bernadette, I need to apologize. I was wrong to tell you who you should be friends with.
Leonard: Should I, um, leave you two alone?
Bernadette: No, Leonard, you should hear this.
Leonard: Okay, good, ’cause I wasn’t really gonna go.
Howard: Look, I know I come off as confident and worldly, but the truth is I’m not.
Leonard: We’re shocked.
Howard: Which is why I tend to feel threatened by other guys.
Leonard: Or loud noises, clowns and nuns.
Howard: But I now realize how foolish that is.
Leonard: He had a panic attack once when he got his head stuck in a sweater.
Howard: It was a full turtleneck. Why aren’t you helping me?
Leonard: I don’t know. Maybe because I’m crazy?
Howard: Bernadette, please, I’m asking you to give me another chance.
Bernadette: What do you think, Leonard? Should I give him another chance?
Leonard: It’s up to you. He didn’t call your experiment stupid.
Bernadette: Come here, tushy face.
Leonard: Tushy face, that is going on Twitter right now.