Have you ever faced a really strong wind, and even felt like it would knock you over? Did you know how fast that wind was blowing? One handy fact: once wind hits 25 miles an hour, flags will blow straight to the side. But you’ll still stay standing up. Wind blowing 100 miles an hour is another story. The guy in this photo is at the top of Mount Washington, and in the video he spends a whole minute trying to walk into the wind. At one point, it knocks him over and blows him sideways across the ice! Wind happens because as the sun warms the ground and air, the warm air rises up above any cooler air. That churning causes wind. Winds of different speeds get different names: breeze, gale, storm, or hurricane. Let’s find out which ones can blow us over!
Wee ones: Which is faster, a “light breeze” at 6 miles an hour, or a “gentle breeze” at 8 miles an hour?
Little kids: If an 8-mile an hour breeze speeds up by 1 mile an hour, how fast does it blow now? Bonus: Wind between 25 and 31 miles an hour is called a “strong breeze.” Does a 29-mile-an-hour wind count as a strong breeze?
Big kids: Any wind speed over 73 mph is hurricane force wind. By how much did this guy’s 100-mph wind beat that? Bonus: If he slid at 100 miles an hour across a giant frozen lake, how far would he travel in 15 minutes? (Reminder if needed: An hour has 60 minutes.)
The sky’s the limit: If you blow across the ice at 100 miles an hour towards your friend, and your friend walks towards you at 20 miles an hour, how far from your starting point do you meet if you start at the same time 60 feet apart? (Hint if needed: It doesn’t matter how far apart you start, or how much time it takes…what matters is the fraction of the distance each of you will move.)
Wee ones: The gentle breeze is faster.
Little kids: 9 miles an hour. Bonus: Yes!
Big kids: By 27 miles per hour. Bonus: 25 miles, since he slides for 1/4 of an hour.
The sky’s the limit: 50 feet from your starting point. For every bit your friend travels, you travel 5 of those same chunks of distance. So of those 6 chunks, your friend slides for 1 of them. 60 feet cut into 6 equal chunks is 10 feet per chunk, so your friend slides just 10 feet while you slide 50.
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.