If you stay up late for New Year’s Eve tonight, by tomorrow you might feel pretty sleepy — and yawn more than usual. Why do we yawn when we’re tired? Some scientists think yawning gives us more energy by putting more oxygen (which is in the air we breathe) into our blood. The funny thing is that yawning seems to be contagious: when one person yawns, other people around him yawn, too! The next time you’re in a group, try faking a yawn — there’s more than half a chance that someone else will yawn within 5 minutes. You can even get your dog to yawn by yawning in front of him. Of course, if he stayed up for New Year’s, he’s probably sleepy, too.
Wee ones: The average yawn lasts 6 seconds. Can you count from 1 to 6?
Little kids: If you yawn and that makes 7 other people yawn, how many of you have yawned in total? Bonus: If you normally sleep 10 hours, but tonight you sleep only from 2 am until 8 am, how much less will you sleep than usual?
Big kids: If you yawn 5 times in one day with each lasting 6 seconds, how many seconds do you yawn in total? Bonus: Say you’re with 24 other kids. You yawn, and within 5 minutes, half of the other kids yawn. Within 5 minutes after that, half of the kids who are left have yawned. How many kids still haven’t yawned?
Wee ones: 1, 2, 3, 4, 5, 6.
Little kids: 8 people. Bonus: 4 hours less, since you sleep 6 hours instead of 10.
Big kids: 30 seconds. Bonus: 6 kids, since you make 12 yawn the first time, then 6 more (half of the 12 who are left) after that, for a total of 18.
Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking before she could walk, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms.