After Bernadette asks Howard how he views their relationship, he makes quite a rash decision after some thinking. During Sheldon's radio interview, Kripke plays an outrageous pranks on him which causes his quest for revenge.
Howard takes Bernadette home after a date. She says three dates mean sex, but wants to know where their relationship is going, and she does not want it to be a one-night stand. She leaves him to think about it.
Howard asks the guys about dating and sex. Kripke comes up and announces Sheldon was going to be on Science Friday on National Public Radio, thus spoiling Sheldon's surprise. Sheldon says his mother is excited and has even invited her Bible study group to listen in. Sheldon has prepared his talking points for the NPR interview, but wonder if the less educated would understand. Then he asks Howard to look the points over for him.
At Apartment 4A Penny enters and immediately asks Raj to talk to her. Raj is stunned. She then asks Howard why he has not called Bernadette in a week. Howard replies he is not sure if she is his type, and says he wants to settle with someone like Megan Fox from Transformers or Katee Sackhoff from Battlestar Galactica. Leonard thinks that he had a better shot with the three-breasted hooker from Total Recall. Howard and Penny gets into an argument and Howard thinks Penny settled for Leonard. Penny says she does not judge Leonard by his appearance. Leonard is offended that they are talking as if he was not even there.
Sheldon's interview on NPR gets ruined as Kripke pumps helium into Sheldon's office, sending his voice up to cartoon sounding levels. Everyone in the cafeteria is listening through the radio and laughs at Sheldon, including his gang. Sheldon soon discovers the nozzle in his office and calls out to Kripke that he is going to murder kill him. Kripke just raises his fists up in triumph.
Howard is relaxing in a bubble bath and imagines himself with Katee Sackhoff. She thanks him for being a part of his masturbatory fantasies. Katee tells Howard that he is hung up on Bernadette and that this sweet and cute girl is actually real. His fantasy ends when his mother yells and tells him that they share that tub.
Sheldon is depressed about being humiliated on national radio, unwilling to leave his bed ever again. Leonard and Raj encourage him to get back at Kripke; even if Raj originally came to mock Sheldon. They make comparisons to The Joker's vengeance on Batman. Sheldon thinks he could kill Kripke with an untraceable chemical; however, Leonard tells him to tone down the prank at a non-lethal level.
After much thinking, Howard comes down to The Cheesecake Factory and proposes to Bernadette. She wonders if that is more comedy that she does not understand. He tells that he'll never find another girl like her that likes him and is real. She calls him insane as they had only three dates and have not even had sex. Howard is willing to do it on her break.
Sheldon has secretly installed a device above the ceiling tiles in Kripke's lab which will mix ordinary dish soap, hydrogen peroxide, and saturated potassium iodide to produce a large quantity of foam. He has even bribed the night janitor with a dollar bill to keep him quiet. Sheldon, Leonard and Raj watch through webcam as the device activates when Kripke and, unfortunately, several members of the university board, including President Siebert, get into the lab. A video from Sheldon starts right away on Kripke's lab computer and says the whole incident has just been uploaded to YouTube; he also thanks Leonard and Raj for their support, thus unwittingly incriminating them. Raj comments that he's running back to India and asks Leonard for his own escape plan.
Bernadette and Penny find Howard at The Cheesecake Factory again. He starts playing and singing a song ("Sweet Bernadette") adapted from 'The Four Tops' "Bernadette", so as to apologize for having proposed to her. Penny also apologizes for Howard's behavior, but Bernadette feels that is the most romantic thing anyone's ever done for her.
- guest starring:
- Teleplay: Richard Rosenstock, Jim Reynolds & Steve Holland
- Story: Chuck Lorre & Maria Ferrari
- "There’s a lot of good stuff in this episode. The writing definitely makes Howard seem more real and more interesting. The dynamic with Bernadette works quite well. The idea of her not understanding his jokes is simple and had plenty of comic potential. It also adds to the idea that she could believably fall for him. His desire to be with even hotter women is understandable and does fit his character. Clearly a relationship with Bernadette would offer more interesting stories for now so it’s nice to see the show go in that direction. As ever Sheldon holds court in typically entertaining fashion. The development of Kripke as a nemesis is a nice idea." - The TV Critic's Review
- IMDb user reviews
- Title reference: Sheldon's revenge against Kripke by dropping a chemical foam from the ceiling in Kripke's lab.
- Chuck Lorre's vanity card.
- This episode was watched by 14.13 million people with a rating of 4.7 (adults 18-49).
- This episode aired in Canada on November 23, 2009 with 1.077 million viewers and a weekly ranking of #29.
- Episode transcript 
- Luckily no one was fired, Raj can stay in the country off-screen.
- Prior towards this episode, Howard doesn't know that three dates with the same women is the threshold for sexual intercourse.
- Bernadette seems much dumber than normal in this appearance. She later claims that she was playing dumb during their initial dates so Howard wouldn't be scared away by her being smarter than him.
- As Penny undermines Leonard, he says, "Again, I’m right here." This is similar to "The Maternal Congruence" (S3E11), when he tells his mother, "Once again, I’m driving. I’m right here." His mother reasons he needs approval.
- Sheldon talks on the radio with Ira Flatow who makes two another appearances.
- Leonard wears a Manta-Ray bomber jacket. Raj first wears his Modified SansaBelt.
- The foam-forming chemical reaction that Sheldon uses to revenge Kripke is a famous experiment known as "Elephant toothpaste". It can be performed premixing concentrated hydrogen peroxide and a liquid detergent (Sheldon uses dish soap), and then mixing the above with a catalyst (Sheldon uses saturated solution of Sodium iodide) that causes rapid decomposition of the hydrogen peroxide. The decomposition produces large amount of oxygen and heat. Foams are formed due to the liquid detergent and the released oxygen, while the heat causes prominent expansion of the foams.
- The song that Howard sings to apologize to Bernadette is following the tune of the song "Bernadette" by the band "The Four Tops".
- Second episode where Raj chooses to mock one of his friends over helping. First was "The Maternal Capacitance" (S2E15).
- First episode with Bernadette to feature her normal voice.
- President Siebert is mentioned but the entire university board is seen at a distance and the president is not yet played by Joshua Malina.
- (Scene: Outside Bernadette's apartment building)
- Howard: So two years later, there’s a knock on the door, guy opens it, and there on his porch is the snail, who says, “What the heck was all that about?”
- (Bernadette giggles for a few seconds)
- Bernadette: I don’t really get it.
- (Howard nods)
- Howard: Well, see, it took two years for the snail to… (she kisses him) not important.
- Bernadette: Can I ask you a question?
- Howard: Sure.
- Bernadette: Where do you think this is going?
- Howard: To be honest, I was hoping at least second base.
- Bernadette: You’re so funny. You’re like a stand-up comedian.
- Howard: A Jewish stand-up comedian, that’d be new.
- Bernadette: Actually, I think a lot of them are Jewish.
- Howard: No, I was just… never mind.
- Bernadette: Look, Howard, this is our third date and we both know what that means.
- Howard: We do?
- Bernadette: Sex.
- Howard: You’re kidding.
- Bernadette: But I need to know whether you’re looking for a relationship or a one-night stand.
- Howard: Okay, just to be clear, there’s only one correct answer, right? It’s not like chicken or fish on an airplane?
- Bernadette: (she is now very cross) Maybe you need to think about it a little.
- Howard: You know, it’s not unheard of for a one-night stand to turn into a relationship.
- (Bernadette glares crossly at Howard for a second and she gives him one quick stern kiss)
- Bernadette: (she is still very cross) Call me when you figure it out.
- (Bernadette now opens the apartment door and walks into its corridors in a huff)
- Howard: Three dates means sex? Who knew?
- (He starts to leave the area)
- (Howard enters Sheldon and Leonard's apartment)
- Howard: Greetings, homies, homette.
- Penny: Why are you back from your date so early?
- Howard: In romance, as in show business, always leave them wanting more.
- Penny: What exactly does that mean?
- Leonard: He struck out.
- Sheldon: What are you talking about?
- Leonard: The cultural paradigm in which people have sex after three dates.
- Sheldon: I see, now are we talking about date, the social interaction, or date, the dried fruit?
- Sheldon: (about his appearance on NPR) My mother is very excited. She's convening her Bible study group to listen in and then pray for my soul.
- Sheldon: All right. These are the talking points for my NPR interview tomorrow. I need to make sure that they're simple enough for the less educated in the audience to understand. Howard, look this over and tell me what's unclear to you.
- Howard: Excuse me, I have a master's degree in engineering from the Massachusetts Institute of Technology. It required the completion of 144 units of grad work and an original thesis.
- Sheldon: Yes. Look this over and tell me what's unclear to you.
- Leonard: You'd have a better shot with the three-breasted Martian hooker from Total Recall (1990 film)|Total Recall.
- Howard: Okay, now you're just being unrealistic. Anyway, that movie was like 20 years ago. Imagine how saggy those things would be.
- (Scene: The Cheesecake Factory. Howard enters.)
- Penny: Oh, gee, you’re too late. Scarlett Johansson and Wonder Woman were just in here trolling around for neurotic, little weasels.
- Howard: Yeah, I came to talk to Bernadette. She’s working today, right?
- Penny: Yes, but I don’t think she wants to see you.
- Howard: Why not?
- Penny: Come on, Howard. You hurt her feelings by not calling her all week. Plus, I’ve kind of been talkin’ some smack about ya.
- (A stern Bernadette is walking by with a tray of two empty glasses in a completely bad mood)
- Bernadette: (she's greeting Howard crossly) Hello, Howard.
- (Howard starts to get her)
- Howard: (he is quivering aggressively) Wait, Bernadette, I need to talk to you.
- Bernadette: (she is so very cross) I can’t now, I’m working.
- Howard: (he is rather nervous) This will only take a second. You asked me to think about where our relationship was going, and I did.
- (Bernadette frowns at Howard for a second as he bends himself down a little bit)
- Howard: Bernadette?
- (Howard pulls her fingers and gets down on his knee whilst Bernadette is shocked by this)
- Howard: (he asks Bernadette nervously) Will you marry me?
- (Penny puts a bill carrier down in disgust)
- Bernadette: (1st time: she's asking Howard crossly) Is this more comedy that I don’t understand?
- Howard: No. I’m serious. I’m never going to find another girl like you who likes me and is, you know, real.
- Bernadette: (2nd time: she's asking Howard crossly) So, this isn’t a joke?
- Howard: (with a loud suspicion) No.
- Bernadette: (she is so very cross again) Then you’re insane.
- (Bernadette storms up the counter and she puts the tray down in a huff)
- Howard: (he's crawling up to her angrily) I prefer to think of myself as quirky.
- Bernadette: (she's slightly confused) Howard, we’ve only been on three dates. We haven’t even had sex yet.
- Howard: (Fair enough. (aggressively) When’s your break?
- Bernadette: (she is so very cross for the final time) Wow.
- (Bernadette now walks away in complete fury. The sound of angry clopping of Bernadette's heels is played to Howard gazing around the Cheesecake Factory for a couple of seconds)
- Howard: Don’t you just hate when this happens?
- Penny: (she's very cross now) Wow.
- Sheldon: Biologically speaking, Howard is perfectly justified in seeking out the optimum mate for the propagation of his genetic line.
- Howard: Thank you, Sheldon.
- Sheldon: Now whether that propagation is in the interest of humanity is, of course, an entirely different question.
(Sheldon is sitting in his office ready to be interviewed via speaker phone by Ira Flatow. Meanwhile, Kripke is in the next room feeding a small hose connected to a helium tank through a hole into Sheldon's office)
- Ira Flatow: (Over the radio) This is Ira Flatow and you're listening to NPR's "Science Friday". Joining us today by phone from his office in Pasadena, California is Dr Sheldon Cooper.
(Kripke proceeds to release helium from the gas tank)
- Kripke: Oh, this is gonna be a riot.
(Cut to Sheldon's office)
- Ira Flatow: (Through speaker phone) Thanks for being with us today, Dr Cooper.
- Sheldon: My pleasure, Ira.
- Ira Flatow: Now, let's talk about magnetic mono-poles. Can you explain to our audience just what a mono pole is?
- Sheldon: Of course. First, consider an ordinary magnet which has, as even the most uneducated...
(Sheldon's voice gradually increases in pitch)
- Sheldon: ...in your audience must know, two poles...
(Sheldon clears his throat, his voice is still increasing in pitch)
- Sheldon: ...a north and south pole. If you cut that in half, you have two smaller magnets, each with it's own north and south pole.
- Ira Flatow: Dr. Cooper, I think there might be something wrong with our connection.
- Sheldon: No, I hear you fine. As I was saying, an ordinary magnet has two poles. The primary characteristic of a mono-pole is that it has only one pole, hence, "mono-pole".
(Cut to cafeteria where Kripke is holding a radio, Leonard, Howard, Raj and others are listening and laughing)
- Sheldon: (Over the radio and still high pitched) A requirement for string theory, or M-theory if you will, is the existence of such mono-poles. I myself led and expedition to the Arctic Circle in search of said particles. KRIPKE, I FOUND THE NOZZLE. I'M GOING TO KILL YOU!
(Sheldon lies on his bed, humiliated)
- Leonard: Are you willing to admit defeat?
- Sheldon: I never admit defeat.
- Leonard: Good.
- Sheldon: However, on an unrelated topic, I'm never getting out of this bed again.
- Mrs. Wolowitz: HOWARD!!! WHAT ARE YOU DOING IN THERE?!
- Howard: I'm taking a bath!
- Mrs. Wolowitz: I HOPE THAT'S ALL YOU'RE DOING! WE SHARE THAT TUB!
- Howard: Please don't remind me!
- Penny: Hey, here’s your tip from table seven.
- Bernadette: Oh, thanks.
- Penny: Mm-hmm.
- Howard (on the stage, into a microphone): Testing. Check. Check two.
- Bernadette: Oh, now what?
- Penny: You want me to throw him out?
- Bernadette: (still upset) No, that’s okay.
- Penny: Are you sure? He’s small. I bet I can get a nice, tight spiral on him.
- Howard: I want to dedicate this number to a great gal who I’ve done wrong. (To the tune of the Four Tops song Bernadette) Bernadette, I am so sorry for trying to propose to you, Bernadette, you found it creepy but that’s just the kind of thing I do. I know now it was too soon to talk of love. It was just a crazy idea that came to me in my tub. But, Bernadette, give me one more chance, sweet Bernadette, I’ll get the hang of this thing they call romance, sweet Bernadette, I dream to once again kiss your lips, sweet Bernadette. Sincerely yours, Howard Wolowitz, Bernadette…
- Penny: Oh, I am so sorry.
- Bernadette: Are you kidding? That’s the most romantic thing anyone’s ever done for me.
- Howard:' (still singing) …Bernadette! Thank you, Cheesecake Factory!