Empty Beer Bottles Make Better Weapons
Stephan Bolliger is one of Switzerland's leading forensic pathologists, and he often appears in court to testify as an expert witness. He isn't stumped very often by the questions he is asked, but it happened last year, with this one: can a beer bottle, when used as a weapon, put a crack in the human skull? To find out, Bolliger set up an experiment, the results of which were published in The Journal of Forensic and Legal Medicine in April.
Other scientists had already calculated how much energy it takes to crack the human skull — between 14 and 70 joules, depending on the location — so all Bolliger needed to do was to take the same measurements on a beer bottle. "If the bottle is more sturdy than the skull," he says, "then the bottle will win, and the skull will break." Simple as that.
Bolliger, who is head of forensic pathology at the University of Bern, went to the store and picked up 10 half-liter bottles of Feldschlösschen Original — his nation's most popular brew. He emptied six of them, left four full and, using a precisely calibrated energy-measuring device, started dropping a steel ball on the bottles from various heights. Bolliger's conclusion: Full bottles shatter at 30 joules, empties at 40, meaning both are capable of cracking open your skull. But empties are a third sturdier.
Why the difference? The beer inside a bottle is carbonated, which means it exerts pressure on the glass, making it more likely to shatter when hitting something. Its propensity to shatter makes it less
PHOTO ILLUSTRATION BY REINHARD HUNGER
SET DESIGN BY SARAH ILLENBERGER Enlarge
sturdy — and thus a poorer weapon — than an empty one. As for the ubiquitous half-full bottle, if you hold it like a club, Bolliger says, "it tends to become an empty bottle very rapidly."
Now that we have scientific proof of the skull-crushing potential of glass beer bottles, should breweries switch to softer materials, like aluminum or plastic? Bolliger says he hopes not. "Beer," he says, "just tastes better out of glass."
http://www.nytimes.com/projects/magazine/ideas/2009/#e