The informant says she heard the following joke from a student at the University of Southern California: “I heard this one on, um, a—a hiking trip I went on . . . and it was a nighttime hike and we were looking at the stars, and the guides were telling astronomy stories and stuff, but one of them, uh, he told this dirty physics joke.”

The joke follows: “It’s uh, based on the Heisenberg Uncertainty Principle, which, uh, I guess states something like, ‘If you know something—object’s position, then you can’t know its velocity and vice versa, if you know something’s velocity you can’t know its positions.’ So the joke is, uh, ‘Why was the physics, uh, the physics student, er, um, bad in bed? Because every time he found the right position he didn’t have the right velocity, and every time he had the right velocity he couldn’t find the right position.’”

The informant likes to retell this joke to people she knows are studying math.

She finds the joke funny because it makes light of a serious and unfortunate situation.

The joke is clearly intended for an educated audience; to understand the Heisenberg Uncertainty Principle, even with an explanation, requires some small knowledge of atomic structure. The Principle refers especially to electrons, which are so small that they’re hard to place. The telling of the joke might even be seen as somewhat of a status symbol—if you get the joke, you’re “in.” The joke of course has a terminus post quem of the proposal of the Heisenberg Uncertainty Principle.