Research shows that teenagers’ body clocks are set to a schedule that is different from that of younger children or adults. This prevents adolescents from dropping off until around 11 p.m., when they produce the sleep-inducing hormone melatonin, and waking up much before 8 a.m. when their bodies stop producing melatonin. The result is that the first class of the morning is often a waste, with as many as 28 percent of students falling asleep, according to a National Sleep Foundation poll. Some are so sleepy they don’t even show up, contributing to failure and dropout rates. Indeed, no one does well when they’re sleep-deprived, but insufficient sleep among children has been linked to obesity and to learning issues like attention deficit/hyperactivity disorder. You’d think this would spur educators to take action, and a handful have.