Cursory Glance Reveals Balloon Boy Fallacy

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There’s a very logical reason everyone should have known Falcon Heene wasn’t on the balloon everyone watched so raptly yesterday. But it’s not what you think.

Everyone wondered if the balloon was actually the right size to hold enough helium to carry him. Here’s some rough, back-of-the-napkin calculations, based on data from CNN and casually Googled:

Assume Falcon weighed about 50 pounds. Assume the lifting capacity of helium is .067 pounds per cubic foot. Divide 50 pounds by .067 and it equals 746.3. It would take 746 cubic feet of helium to lift our hypothetical Falcon.

Assume (as per CNN) the craft was roughly a cylinder 20 feet in diameter and 5 feet high. The volume of a cylinder is the area of the base times the height. (Area of the base = pi x radius^2 = 3.142 x 10′ x 10 = 314.2 square feet.) The volume of the craft, 314.2 square feet, times 5 feet is 1,571 cubic feet.

It was totally conceivable that the balloon could carry Falcon. So why, then, was it obvious he wasn’t in there?

Look at the shape of the balloon in flight in the video above. If there had been a 50-pound weight in the bottom of the balloon, it would have deformed the shape, just like the weather balloons we’re all familiar with.

Image from the NOAA archive.Image from the NOAA archive.

Image from the NOAA archive.

The bottom would have been pulled downward by the ballast of a passenger. But it wasn’t. It held its unladen shape, and even began to obviously deflate without being stretched out by its hypothetical (and ultimately nonexistent) load. So I guess the real mystery is why none of the media professionals thought about this while the hunt was on. Probably wouldn’t have made for good ratings, I guess.

Special thanks to reader Michael Hale who e-mailed us asking for a “scientific” evaluation of the event.

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