Stone equally likes teaching non-specialists about his research.

Within his third-floor Pierce Hall office, interspersed among journals, books and photographs, Stone has numerous containers of fluids on display.

Between discussions of Harvard athletics ("I like watching good athletes play," he says. "I don't take winning and losing quite as seriously as most.") and his time as a postdoctoral fellow in Cambridge, England ("I go back there almost every summer," he says.), Stone paused in an interview last week to disprove the common belief that toilets flush in one direction in the Northern Hemisphere and a different direction in the Southern hemisphere.

Shaking a contraption that resembles two soda bottles attached at the mouth, Stone demonstrated that the direction in which the water flows between bottles depends only on the way in which one shakes the bottles.

"It's just blatantly false," he says.

Despite his passion for fluids (his collection includes dyes and slime, among others), Stone did not always intend to become a chemical engineer.

"I came to college pre-law and intended to major in political science," he says. "I guess I watched too much television in high school."

Nevertheless, since earning his Ph.D. from Cal Tech in 1988, Stone has become an active researcher in mechanical engineering and enjoys the impact his career choice has made on his life.

"Not all of my close friends live in Cambridge. They happen to live in places like the other Cambridge or Pasadena," he says.

"To me, that's a very interesting part of research," Stone adds.