National Center for Families Learning
Ncfl: Wonderopolis: Can You Get Too Much Sleep?
Have you ever wondered about how much sleep you need? Watch a short video, read grade level text, and take an interactive quiz about the science behind sleep.
BBC
Bbc: Sleep: Daily Rhythm Test
Answer these four questions about your sleep habits, then see a graphic representation of your natural circadian rhythm of alertness and sleepiness over a 24 hour period.