# Freeze-Frame Falls

Here's your nightly math! Just 5 quick minutes of number fun for kids and parents at home. Read a cool fun fact, followed by math riddles at different levels so everyone can jump in. Your kids will love you for it.

# Freeze-Frame Falls

March 5, 2014

As we were saying the other day, this winter has been ridiculously cold for the northeast U.S. — to the point where one of the world’s largest waterfalls has frozen twice. Niagara Falls, a set of three giant waterfalls on the border between the U.S. and Canada, normally send 6 million cubic feet of water over the cliff every minute. But with subzero temperatures and daily highs of only about 9 degrees, the water has actually frozen. It’s hard for moving water to freeze, but whole sections have turned into giant solid billows and balls, lit by fun colorful lights that normally shine on gushing water. Meanwhile, ice caves on Lake Superior have formed beautiful icicles that usually can’t form in normal winter weather, and for the first time since 2009, the lake is frozen enough for people to walk across it to visit the caves. Lots of cool, amazing things to see, if you’re willing to go outside.

Wee ones: The last time Lake Superior froze enough to walk to the caves was in 2009. Had you been born yet, and if so, how old were you?

Little kids: If it reached 9 degrees at Niagara Falls on Monday, but will start 2 degrees higher than that tomorrow, how “warm” will it be tomorrow morning?  Bonus: If water can melt at 32 degrees, but thanks to sunshine the Falls could start melting 4 degrees less than that, at what temperature will they start thawing?

Big kids: The Falls have drops as steep as 165 feet. About how many times as high as a 20-foot-tall house is that?  Bonus: Some water is still flowing alongside giant icicles. If of the 6 million cubic feet of water per minute, 1/4 of it is still moving, how many cubic feet per minute are still flowing? (Hint: To find 1/4 of a number, cut it in half, then cut in half again).