Last week, I looked at deflate-gate (the Patriots ball inflation “scandal”), and ran some numbers.<\/p>\n
I used \u00b0F, and figured that if the balls were filled up to 12.7 psi at 70\u00b0F, and they cooled to 20\u00b0F, you would get a pressure drop of 1.38\u00b0F. <\/p>\n
Boyle’s law is PV=nRT, where P=pressure, V=Volume, n=the amount of the gas in moles, R=the ideal gas constant, at T=temperature.<\/p>\n
Since in the football, volume, amount of gas, and the ideal gas constant remains the same, so we can reduce this to:<\/p>\n
P1<\/sub>\/T1<\/sub>=P2<\/sub>\/T2<\/sub><\/p>\n Then we can solve for P2<\/sub>: P2<\/sub>=(P1<\/sub>\/T1<\/sub>)T2<\/sub><\/p>\n So, the math looks good, where is the “Jive Ass Newbie Mistake?<\/p>\n Because the pressure in the football isn’t<\/b> 12.5 psi it’s 27.2 (12.5+14.7) psi.<\/p>\n Boyle’s law is based on absolute<\/b> pressure, not gauge<\/b> pressure. Gauge pressure is the difference between the absolute pressure of what you are measuring and the atmospheric pressure.<\/p>\n I am a complete tool for screwing this up.<\/p>\n It turns out that using absolute pressure, a 31 degree ball will be 2.076 psi under-inflated.<\/p>\n So, “Ball-Gate” is largely just an effort by Roger Goodell to make people forget that he is an incompetent and corrupt liar. (Ray Rice and Chronic Traumatic Encephalopathy, two name just 2)<\/p>\n Full disclosure: My wife is a Patriots fan, though I’m not.<\/p>\n I’ll be watching the Superbowl for the ads.<\/p>\n (On edit<\/i>) (2nd<\/sup> edit<\/i>) Still, I will apologize here.<\/p>\n","protected":false},"excerpt":{"rendered":" Last week, I looked at deflate-gate (the Patriots ball inflation “scandal”), and ran some numbers. I used \u00b0F, and figured that if the balls were filled up to 12.7 psi at 70\u00b0F, and they cooled to 20\u00b0F, you would get a pressure drop of 1.38\u00b0F. Boyle’s law is PV=nRT, where P=pressure, V=Volume, n=the amount of …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1010,1064,1069,1057],"tags":[],"class_list":["post-183211","post","type-post","status-publish","format-standard","hentry","category-bureaucracy","category-media","category-science","category-sports"],"_links":{"self":[{"href":"https:\/\/www.panix.com\/~msaroff\/40years\/wp-json\/wp\/v2\/posts\/183211"}],"collection":[{"href":"https:\/\/www.panix.com\/~msaroff\/40years\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.panix.com\/~msaroff\/40years\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.panix.com\/~msaroff\/40years\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.panix.com\/~msaroff\/40years\/wp-json\/wp\/v2\/comments?post=183211"}],"version-history":[{"count":0,"href":"https:\/\/www.panix.com\/~msaroff\/40years\/wp-json\/wp\/v2\/posts\/183211\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.panix.com\/~msaroff\/40years\/wp-json\/wp\/v2\/media?parent=183211"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.panix.com\/~msaroff\/40years\/wp-json\/wp\/v2\/categories?post=183211"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.panix.com\/~msaroff\/40years\/wp-json\/wp\/v2\/tags?post=183211"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
There also might be water vapor in the air used to inflate the ball that would further exacerbate the pressure drop as it condenses.<\/p>\n
I just realized that I had not posted this on my blog before, the screw up was on a comment I made on Facebook.<\/p>\n