Regarding deflate-gate
Amounton’s Law says
“The pressure of a gas of fixed mass and fixed volume is directly proportional to the gas’s absolute temperature.”
So P/T = Constant
For comparing the same substance under two different sets of conditions, the law can be written as:
P1/T1 = P2/T2
I’m also going to do this in metric to avoid other potential errors. And I apologize that I am 30 years from doing this sort of work
12.5 psi = 86.18 kPa ( kiloPascals)
75F=23.89C = 297.04K
30F=-1.11C = 272.04K
So
86.18/297.04 = P2/272.04
0.29= P2/272.04
P2=78.93kPa
78.93kPa= 11.45PSI
Temperature change from 75F to 30F degrees would result in a football ball losing ~1 pound of pressure per square inch.
Now this does not account for ALL of the claimed 2lbs PSI that was measued as having been lost — but we don’t know that the ball began at 12.5 — what if they began at 12? What if they were inflated in a 78 degree room?
I think early calls dismissing temperature as a force are hasty.
http://en.wikipedia.org/wiki/Gay-Lussac%27s_law#Pressure-temperature_law
UPDATE
Someone pointed out that
Pressure gauge= Pressure absolute – Pressure atmosphere
which means I need to do my calculations with absolute pressure to use the Ideal Gas Law
Atmospheric pressure is 14.7 psi
12.5 + 14.7 = 27.2psi = 187.54 kPA
187.54/297.04 = P2/272.04
0.29= P2/272.04
P2=171.76kPa
171.76kPa= 24.91psi
subtract atmospheric pressure and
24.91-14.7= 10.21psi
!!!!
A ball inflated at 75 degrees to 12.5 psi will be 10.2 psi at 30 degrees!!! This matches the readings by the NFL Officials!!
UPDATE REDUX
187.54/297.04 = P2/272.04
P2=178.07kPa
171.76kPa= 25.82psi
subtract atmospheric pressure and
25.82-14.7= 11.15psi
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