Poppy seeds, a glove, sticky tape, and a loudspeaker attached to a plastic cylinder. Those were the tools that 398 high school students from 84 countries were given to investigate a phase transition. The task was part of the 47th International Physics Olympiad, which took place in Zürich for a week in July.
The loudspeaker made the seeds jump, and below a certain amplitude the seeds spontaneously gathered to one side of a barrier. This may have been “the most entertaining and counterintuitive experiment in years,” says Paul Stanley of Beloit College, a longtime coach of the US team. “Add to that, poppy seeds are illegal in some of the participating countries!”
In a second experiment, students investigated electrical conductivity in two dimensions. The three theory questions involved nonlinear circuits, subatomic particle detection at the Large Hadron Collider at CERN, and mechanics; the two-part mechanics question challenged students to figure...
