Intel International Science & Engineering Fair: The physics roundup
Choosing which projects to highlight from the 75 physics exhibits here at the Intel International Science & Engineering Fair was tough, but we waded through high-energy protons, the kinetic behavior of liquid marbles, chaotic double pendula, and negative refractive indices. Then we spent some time looking at a few questions we've actually occasionally pondered ourselves.
First: why does fabric appear dark when it's wet? Ragnhild Cassel Novel of Bergen, Norway (a town which is wet a lot) spent a long time thinking about that. "It's something you see every day -- with your hair when you shower, your clothes...," he says. And yet most of us have no idea.
Novel hypothesized that wet fabric is a lot worse at reflecting light than dry fabric. Because the water droplets create an additional surface for light waves to maneuver around, the light is more likely to pass through the fabric, rather than be cleanly reflected. Since the presence of reflected light is how our eyeballs see, this absence of reflected light would make wet fabric appear darker.
This turned out to be the case. Novel measured wavelength intensity on the other side (from a light source) of wet and dry fabric, and found that far more light passed through the wet fabric. This is cool, if not immensely practical, but "you never know," she says. "One day it might have an application."
Second: What will WD-40 do to my shoes? C'mon, you can admit you've thought about that. The answer? It depends what kind of shoes and what you're walking on. If you're wearing tennis shoes, according to a project by John Patrick Boggs of Aberdeen, South Dakota, the answer is nothing. Climbing shoes, however, got a lot more traction on both wood and ceramic tile after application of WD-40. That increase was particularly pronounced on ceramic tile.
We think this means that if we want to go climbing on ceramic tile, we should apply WD-40 to our climbing shoes to keep from slipping but, alas, Boggs disappeared from his booth before we could ask him this question -- and why he'd think that WD-40 would increase friction, when all we've ever used it for is to loosen stuck hinges.
Third: If we want to build a cosmic ray detector, should we put it on New York City rooftop water tanks? It turns out, according to a project from Yvette Leung and Pragya Kakani of Jericho, New York, that placing cosmic ray detectors on rooftops is an extremely efficient way to collect reasonable data on the origin and direction of these rays, which hurtle toward earth at tremendous speeds. (Incidentally, Roald Hoffmann, who shared the 1981 Nobel Prize winner in chemistry, also looked at the properties of cosmic ray particles for his Westinghouse Science Talent Search project in the 1950's -- see our "Where Are They Now?" profile on him, posted Monday).
The equipment for building a rooftop data collection point cost just $4,000, vs. $50 million (the exhibit information said) for the Pierre-Auger Observatory. Frankly, we think our rooftop water tanks have been a little bored lately, so if keeping them useful is this cheap, sign us up!
