Why owls get lower grades
Those with late chronotypes — owls — earned significantly lower grades in science (except for physics) and math, even if they got a full night’s sleep. However, they did as well as their lark classmates when they took exams in the afternoon. Chronotype did not affect performance in humanities/linguistic subjects.
Teens often are owls. Some British schools have experimented with later start times — as late as 10 am — to help students do their best, writes Hasselmann. He also suggests scheduling science classes for the afternoon.