. Suppose you are watching the 2018 Pyeongchang Winter Olympics. A world-famous
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. Suppose you are watching the 2018 Pyeongchang Winter Olympics. A world-famous figure skater begins her routinc. The temperature of the ice is 25 °F. Legendary sports commentator Bob Costas smugly explains that the increased pressure under the skate of the Olympian (who weighs 125 lbs) is causing the ice to melt at lower temperatures, allowing for her to glide so effortlessly across the ice on one foot. Is legendary sports commentator Bob Costas correct? Calculate how much the pressure under the figure skater's blade reduces the melting temperature. Explicitly list any assumptions you make.Explanation / Answer
No, Bob Costas is not correct. Scientist have calculated the change is freezing point of water at different pressure and back it up with experiments. To lower the freezing point of water from 0°c to -1°c you must apply pressure more than 121 times the pressure of the atmosphere bearing down on your head right down. Assuming that the skaters weighting 125 lbs (~57 kg). The blade of each skate in contact with the surface is about 3 mm wide and 200 mm long. Pressure is the force applied to a specific area. The 58 force pressing down on the ice is 57kg multiple by gravity which has a value of 9.8newtons per kg. So a force of 558 Newton's is pressing down on the blade of the skate. To calculate the pressure we need to know the area of the blade in metres.3 by 200 mm is0.003 by 0.2m, an area of 0.0006 SQM.The pressure is the force 558 newtons divided by this area, which is 913000 newtons per metre square.Hence the skater would have to apply a pressure is 120 times atmospheric pressure they would have to weigh ten times as much as normal ice skater, and so be about 558kg.
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