|2011-02-21 14:03:08||John McLean Miscalculation|
Thought you might be interested in another McLean rant that seems to have its basic physics that he claims to know so much about all wrong.
Here he is claiming 1m of seawater has the same heat capacity of 3300m of atmosphere.
A few calculations seem to prove that the heat capacity he claims is out by a factor of 855. But it is a while since I did tertiary physics so I wouldn't mind a cross check.
Values for specific heat capacity Cp
Air: 1.0035 J/(g*K)
fresh Water: 4.1813 J/(g*K)
The density of air at sea level and at 15Â°C according to ISA (International Standard Atmosphere), air has a density of approximately 1.22521 kg/m3.
At 3300m it is about 72% of sea level, basically linear reduction with height. So in the first 3300m density is an average 86% of SL or 1053.5 kg/m3.
1m of Seawater; density is 1025kg/m3, specific heat capacity 3993 J /kg/K @20 degrees.
SL density/m3 1025 1.22521
density factor 1 .86
av/density kg/m3 1025 1.0535
height 1 3300
actual kg 1025 3663
kj/kg/K 3993 1003.5
kj/K for "x"amount
depth (m) Kj/K of this mass Ratio
1.225 0.86 3300 1057 1004 1060887 0.259 of water 1025
1025 1 1025 3993 4092825 3.857926 of air
seawater @20C 1025kg/m3
In other words the first 3300m of atmosphere has a bit more than a quarter of the heat capacity of 1m of water.
So McLeans conclusions as to relative heat capacities of atmospheric air to water are out by a factor of 3300/3.857926 or 855.
He canâ€™t even claim a decimal point error with any more conviction than the rest of his bodgy unqualified theories.