'Up' and the Math-Challenged.The premise of this summer's Disney/Pixar hit movie "Up" is that an old guy named Carl ties thousands of helium balloons to his house. The balloons rip the house from its foundation and whisk Carl and a young stowaway off on a grand adventure in South America. We saw it and thought, what a great movie. Other people saw it and thought, could you really do this? And if so, how many balloons would it take? The people at Wired magazine's "Wired Science" blog reckon it could be done, assuming you can find 105,854 balloons and enough helium to fill them. They got a house mover to estimate that Carl's house would weigh about 100,000 pounds.
Air weighs about 0.078 pounds per cubic foot; helium weighs just 0.011 pounds per cubic foot. So a helium balloon experiences upward force equal to the air it displaces minus its own weight, or 0.067 pounds per cubic foot of helium balloon. So to exert 0.067 cubic feet of buoyancy on each of the house's 100,000 pounds, you'd need 1,492,537 cubic feet of helium. A three-foot spherical balloon has a volume of 14.1 cubic feet, so you'd need 105,854 of them. You get your daughter's Barbie Dream House, a bunch of balloons and a tank of helium, and next's year's Science Fair project is all taken care of. REPRINTED FROM THE ST. LOUIS POST-DISPATCH. DISTRIBUTED BY CREATORS SYNDICATE INC.
|
 |
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
