Professor Mya places a single sugar crystal in the center of a clear chamber. "Observe," she whispers.

Question on the slate: “Compare the area under the cold curve to the area under the hot curve. What do you notice?”

"Which is why," Mya says, "a small fever can help you fight infection faster. And why a few degrees of global warming can radically speed up chemical reactions in the atmosphere."

Carlos stares at the curve. "The line starts at zero on the vertical axis when speed is zero," he says. "So… none? Every spore is moving at least a little?"