If you’ve ever tried to hold your breath, you know how it gets harder and harder as time ticks by. Even after 10 seconds it’s tough, right? Your body needs air, so it will try to “inhale” (pull air in) no matter how hard you try not to. But sea creatures that need air can hold their breath a REALLY long time. Whales and dolphins are mammals, not fish, so they need air. So do seals, turtles, and penguins. And think about sea-diving birds: it’s hard to dive into water to grab fish for dinner if you have to keep coming up for air! Many of these birds can hold their breath for a whole 10 minutes, and the emperor penguin can hold it for 20. That’s about the same as a dolphin. But the whale is the winner: sperm whales can swim without breathing for almost 2 hours!
Wee ones: Try holding your breath and counting to 5 in your head! What numbers do you think?
Little kids: If you hold your breath for 10 seconds and count down from 10, what numbers do you say now? Bonus: If a seagull can hold its breath for 10 minutes but an emperor penguin can hold for 20, how many minutes longer can the penguin last?
Big kids: If a dolphin needs to store up air for 4 minutes before going under for 27 minutes, how long does that all take? Bonus: A sperm whale can hold its breath for 2 hours if resting, but 20 minutes less than that if it’s swimming hard. How long can it hold while swimming?
The sky’s the limit: If you could hold your breath for 20 minutes, and you can turn an underwater somersault every 15 seconds, how many somersaults can you do without taking a breath? (A minute has 60 seconds, and a hint if needed: first figure out how many somersaults you can do in 1 minute.)
Answers:
Wee ones: 1, 2, 3, 4, 5.
Little kids: 10, 9, 8, 7, 6, 5, 4, 3, 2, 1. Bonus: 10 more minutes.
Big kids: 31 minutes. Bonus: 100 minutes, since 2 hours is 120 minutes.
The sky’s the limit: 80 underwater somersaults, since you can do 4 per minute for 20 minutes.

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.