February 26, 2013, 11:48 AM —
Image credit: Flickr/STILLNESS FKL
My son often has expressed a desire to be bitten by a radioactive spider so that he could become Spiderman, his favorite superhero.
Since he's actually afraid of spiders, this is probably more a conceptual than real-life desire. Either way, he wants to believe Spiderman will be there to protect us from Green Goblin, Sandman, Rhino and Doc Ock.
But every superhero is only as good as the tools in his or her crime-fighting bag, and I've often wondered how Spiderman's webbing -- effective in so many contexts and situations -- could contain a powerful villain like Rhino, never mind stop a runaway train from plummeting over the end of the track and killing all the passengers, as nearly happened in Spiderman 2, starring Tobey Maguire, Kirsten Dunst and James Franco.
Now, thanks to physics students at the University of Leicester in England, I too can believe in Spiderman.
The students set out to answer one question: Could a material with the strength and toughness of a spider's web really stop four crowded subway cars? Their answer:
A group of three fourth-year MPhys students calculated the material properties of webbing needed in these conditions - and found that the strength of the web would be proportional to that of real spiders. Their paper, Doing whatever a spider can, was published in the latest volume of the University of Leicester's Journal of Physics Special Topics.
Students James Forster, Mark Bryan and Alex Stone first calculated the force needed to stop the four R160 New York City subway cars. To do this, they used the momentum of the train at full speed, the time it takes the train to come to rest after the webs are attached, and the driving force of the powered R160 subway car. The students found the force Spiderman's webs exert on the train to be 300,000 newtons. They were then able to calculate the strength and toughness of the webs.
Well, it turns out that the "Young's modulus" -- or stiffness -- of the web would be 3.12 gigapascals, which puts it within the range of silk spun by orb-weaver spiders. And the silk's toughness was calculated at nearly 500 megajoules per cubic meter, the equivalent of silk spun by Darwin's Bark Spider, which previous researchers have said makes webs "more than twice tougher than any previously described silk, and over 10 times better than Kevlar."
Let this be a warning to you super villains out there. This stuff's real.