It’s National Roller Coaster Day, when we celebrate our wildest amusement park rides. Giant curvy tracks give us a top-speed train ride straight down out of the sky. It’s been said the first roller coaster ever was built in Russia way back in the 1600s. It was built of wood on a mountain of ice, and was only about 70-80 feet tall. Today’s tallest roller coaster, the Kingda Ka at Six Flags Great Adventure in New Jersey, tops out at 450 feet! Kingda Ka riders zoom at 128 miles an hour, and the very fastest coaster, the Formula Rossi in the United Arab Emirates, runs at 149 miles an hour — in case the other was too slow for you!

*Wee ones:* If the roller coaster sends you down 5 steep hills, what numbers do you scream out to count them?

*Little kids:* If the coaster takes 2 seconds for the first drop and the whole ride is 10 times as long as that, how long is the ride? *Bonus:* How many seconds after that 2 seconds do you still have to survive?

*Big kids:* How many feet taller than that long-ago 80-foot coaster is the 450-foot Kingda Ka? *Bonus:* If it were 20 times as tall as your 20-foot-tall house, how tall would it be?

*The sky’s the limit:* It turns out that 22 feet per second is the same speed as 15 miles an hour. If the coaster sends you down 176 feet in just one second, how many miles an hour are you traveling?

Answers:

*Wee ones:* 1, 2, 3, 4, 5.

*Little kids:* 20 seconds. *Bonus:* 18 seconds.

*Big kids:* 370 feet. *Bonus:* 400 feet — pretty close to its real height!

*The sky’s the limit:* A speedy 120 miles an hour. 176 feet per second is 8 times 22, so you’re going 8 x 15 miles an hour.