# Solve This: Perpetual Motion

June 27, 2016
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Ed’s son, Lil Johnny, came running into the living room all enthused. “Hey dad, the teacher said that there’s no such thing as a perpetual motion machine. But She’s wrong! Here, take your eyes off the TV and put ‘em on this!”

Little Johnny had drawn a picture of a tall metal water tank. It had a hole near the top and one near the bottom. Water was shown gushing out of both.

“Ya see Dad,” said Lil Johnny professorially. (He often spent hours reading the family’s 40-year-old set of encyclopedias) “The water pressure is greater at the bottom of the tank so all ya have to do is connect the top hole and bottom hole through a hose. Because the bottom hole has more pressure the water will flow up the hose and into the top hole. It will go on forever, et voilà, eureka, son-of-a gun! PERPETUAL MOTION!”

Ed had a vague sense that the contraption wouldn’t work. But he didn’t know why.

Can you help?

Here's a little puzzle to ruminate on during a coffee break. Maybe you'll win a gift card! Give it your best shot in the comment section below. Enter as many times as you want. A \$50 gift card will go to the first right answer. We need your email to send the gift card so make sure you're registered (and you have verified your registration via email) when you leave your comment in the box below. We cannot send you a gift card without completed verification (answer the email that asks you to click through to verify)