This Week From Bedtime Math: Catch the Wave

Waves are everyone&s favorite part of the ocean, but how do they work? Come along for the ride and hang 10 in today&s Bedtime Math Challenge!
By Laura Overdeck
Sep 03, 2013



Sep 03, 2013

What is Bedtime Math? A message from Laura: Bedtime Math is a pretty simple idea: We all know we should read to our kids at night, but what about math? My husband and I have done fun, mischief-loaded math problems with our kids at night for years, and when at age 2 our third child started hollering for his own math problem, we realized we were onto something:  In a world where so many people say, "Ewww, math!" we had created a household culture where kids don't just tolerate math, they actually seek it out. Now we email parents a fun, lively math problem every day to do with their kids – and every week, we'll be posting a new problem right here on Scholastic Parents!

If you've ever been to the ocean and played in the waves, you know how strong they are and how much splash they can make. What makes those waves in the first place? They're caused by wind blowing over large areas of the open ocean, which gives the waves lots of power. As they come to shore, the shallower water slows them down, but their power has to stay the same. So, as waves get taller, they slow down by that amount squared. If a wave becomes twice as tall, that means it's now traveling only 1/4 as fast. This is also why waves "break," where the bottom of the wave slows down more than the top, so the top ends up falling over the front and the wave gets all white and frothy. By the way, people can also make waves in wave pools by pumping lots of water into the pool at once -- kind of like a big toilet (although hopefully cleaner). But there's nothing quite as exciting as the real thing at the beach.

See if your kids can make "waves" by correctly answering these math challenges:

Wee ones: If you're 3 feet tall and a 4-foot wave is coming towards you, who's taller? Will the wave splash over the top of your head?

Little kids: If the water is 3 feet deep and the waves are rising 5 feet above the water, how tall are the waves above the ocean floor?  Bonus: If you're paddling at 3 miles per hour on a buggy board and a 10-mile-per-hour wave picks you up and you ride it, how much faster are you going now?

Big kids: When a wave comes and you jump over it, you'd better keep watching because there's probably another wave coming. If the waves are coming every 10 seconds, how many waves do you jump over in 1 minute? (Reminder: a minute has 60 seconds.)  Bonus: If they speed up to once every 4 seconds, now how many waves do you have to jump over every minute?
Wee ones: Yes! The wave is taller than you are.

Little kids: 8 feet in total.  Bonus: 7 miles per hour faster.

Big kids: 6 waves.  Bonus: 15 waves.

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