A bag of popcorn is as unhealthy as a whole day's worth of fatty foods! We can use surprise—an emotion whose function is to increase alertness and cause focus—to grab people's attention. But surprise doesn't last. For our idea to endure, we must generate interest and curiosity. How do you keep students engaged during the forty-eighth history class of the year? We can engage people's curiosity over a long period of time by systematically "opening gaps" in their knowledge—and then filling those gaps. (…) Surprise makes us want to find an answer—to resolve the question of why we were surprised—and big surprises call for big answers. If we want to motivate people to pay attention, we should seize the power of big surprises.