Hansen: Mr. Sheridan, why do motorcycles sound different when they're coming than when they're going away?
Mr. Sheridan: Hansen, I'm trying to eat my lunch. By the time I explained it to you, you would have forgotten the question anyway.
Dewey: I think my brother Malcolm told me about that last summer. "It's called the Doppler Effect, Dewey. Both sound and light travel at a constant speed, but their wavelengths get shorter or longer depending on whether they're moving towards you or away from you. Now put some pants on, you little freak." My imaginary friends are right! I am a genius! So basically, what it means is that the sound waves from a motorcycle move away from it at the same speed in all directions. But if it's coming towards you, then the sound waves get stacked closer and closer together, so the frequency goes up and the sound gets higher. Do you understand?
Hansen: Yeah, I do.
Dewey: Oh, my God! I learned something. I learned something! I learned something! I learned something! I learned something!
Mr. Sheridan: Hansen...
Hansen: I learned something!
Mr. Sheridan: Maybe you shouldn't learn things if you're going to be so disruptive. Now sit down and be quiet.
Dewey: Everyone who hates this, follow me. [kids follow Dewey]