"So," said the physics professor, "behind this curtain we have today's practical experiment. And since we've been studying the principles of buoyancy, you might imagine that this is a tank of water." He pulled a thick rope and the curtains parted. "You'd be right. "What you might not have expected are the famous artists Marcel Marceau and Charlie Chaplin, here to help demonstrate. Applause, please." The auditorium of students clapped obediently. "Now, what do you think will happen when they fall into this tank of water? Marie."

Marie stood. "Chaplin is older — pardon, Mr Chaplin — and thinner, so I'd guess he's denser, and will reach the bottom first."

"Okay, anyone else want to venture a guess? Oscar."

Oscar stood. "Marceau's wearing tighter clothes, and Chaplin's are baggier, so Mr Marceau will have less drag. He'll hit bottom first."

"Very good," the professor said. "Show of hands, who agrees with Marie? And who agrees with Oscar? Well, let's see." He pulled a lever, dumping both performers into the water. Once the turbulence settled, the two men sank and touched bottom at the same moment.

"You all forgot one of the fundamental principles," said the professor. "Great mimes sink alike."