PROVIDENCE, R.I. [Brown University] — The nearly 40 students in Jia Li's class at Brown University leaned in as he approached the climax of his lesson on artificial gravity.
Li, an assistant professor of physics, held a few pieces of pink string in one hand. Dangling from the string was a silver tray with a water-filled wine glass on it. Li started to swing the tray like a pendulum, assuring students he’d be able to swing it over his head without spilling a single drop. “It will be as if there’s this imaginary hand holding it all,” he said of the experiment known as the Greek waiter’s tray.
A few students looked away as Li let it rip, bringing the tray over his head in a blur of dizzying swirls. Nothing spilled. Nothing shattered. And after Li returned the tray to a slow pendulum-like swing, the class broke out with a round of applause.
“I’ll admit, I was bit nervous,” Li told them, smiling, before he launched back into the bulk of his lecture.
Unseen in the classroom — but integral to the success of this experiment — was Angella Johnson, demonstration manager for Brown’s Department of Physics.
“When faculty in the department want to show certain principles in their class, I’m someone they can reach out to,” she said.