Sheldon: They're very different. Physics answers the question: what is the nature of the universe? Geology answers the question: you know, what'd I just trip over?

Sheldon: I've been modeling different types of dark matter and the traces they would leave on the zircon inside your meteorite.
Bert: What's this one here?
Sheldon: That's actually a dark matter model of my own creation. I call it the Cooper Boson.
Bert: Cool. I got to name a rock once. I named it Moderately Sedimented Shale. Guess I kind of pooped the bed on that one.

Amy: What's going on?
Sheldon: What if there was something I wanted to do, but I was worried other people would think less of me?
Amy: Is that other person me, and does it happen in the bedroom, in which case I think I'm cool with it?
Sheldon: No. It's about working with Bert on - You know what? I'm not even gonna say it. I am just gonna say the letter it starts with and -"ology". G-- Oh, no, that's not gonna work.

Leonard: Hey, how's Bernadette handling bed rest?
Howard: She lies around all day eating Mallomars and hollering at me, so her transformation from my wife to my mother is complete.
Sheldon: Congratulations. I know that's what you were hoping for.

Penny: All right, just give her some space, all right? Don't call, don't text, don't e-mail.
Raj: That's crazy. What if I see a sunset that reminds me of her?

Raj: So Ruchi and I decided to keep things casual.
Penny: (scoffs)
Raj: What? What? I can handle casual.
Penny: (scoffs)
Raj: Oh, why do you keep doing that with your face?
Penny: Because you keep saying stupid things with yours.

Howard: Are you guys working together on that meteorite project?
Sheldon: (sighs) Yes, fine, you found me out. I'm doing geology. Just, please, don't tell anyone.
Bert: Are you embarrassed of me?
Sheldon: Oh, no, no, no, not you. No, just the work that you've devoted your entire life to.

Amy: Sheldon, you've never cared what people thought, even when you really, really should. That dinner with my parents comes to mind.
Sheldon: If I'm not gonna use "your momma" jokes when I meet your mother, why'd I bother to learn them?

Raj: Are you saying that you don't believe two people fall in love?
Ruchi: Of course they do. It's just that what people call "love" is actually a series of biochemical reactions in the brain that fade over time.
Raj: Yes. Like the old song, "When a man has a biochemical reaction for a woman."

Sheldon: Uh, let's-let's do it here, in-in the evenings, after everyone's gone home.
Bert: I just have to see if my evenings are free. That's a joke. They are.

Bert: Well, you know, we geologists always get a little sad when Rocktober's over.

Bert: Hey, Sheldon.
Sheldon: I've been thinking about it, and I suppose I could help you with your research.
Bert: What changed your mind?
Sheldon: Bert, I'm a gift horse. Don't look me in the mouth.

Bert: I'm not asking you to play rocks. I'm asking you to collaborate on a research project. Although, if there's time, I guess we could play a round of zinc, zinc, piece of quartz.

Sheldon: Penny, this is serious. My reputation is on the line. What are people gonna think when they see us collaborating?
Penny: I don't know. Poor Bert?

Penny: Okay, this is about science. Why'd you come to me?
Sheldon: Well, because it's also about my reputation. And somehow you manage to hold your head high despite your checkered past.
Penny: Checkered past?
Sheldon: It's a figure of speech referring to how sexually promiscuous you were.
Penny: Really? Well, I've got a figure of speech about how sexually promiscuous you can go be with yourself.