No, the pressure won't increase over time, unless the model itself breaks (i.e., by radiating away too much energy, melting the column, or destroying the column with high-speed CO2 molecules, etc.). To get some idea about how this might actually work, see the following web page re stacks of superballs: http://www.physics.gla.ac.uk/~kskeldon/PubSci/exhibits/D12/ I seem to recall a video of this type of demonstration somewhere on the internet, but haven't been able to find it. Needless to say, one model for the CO2 column (or any air column) is a stack of superballs. At 02:49 PM 8/1/2006, franktaw@netscape.net wrote:
That would be the initial condition. However, the internal pressure will increase, up to the point where the amount of CO_2 being blown out the other end matches the input. That will require a _lot_ of CO_2 to be pumped in, and hence a large increase in the pressure.
Franklin T. Adams-Watters
-----Original Message----- From: Henry Baker <hbaker1@pipeline.com>
If I remember my physics correctly, air pressure is approx. 14.7#/sq in, which is the weight of the entire column of air 1 inch square sitting on the square inch.
According to a source on the internet, standard air has an average molecular weight of ~29, while CO2 has a molecular weight of ~44.
So I would estimate that the same column of pure CO2 would produce a pressure of approx 22.3#/sq in.
This would mean that to pump pure CO2 into the "stack", it should take a head pressure of 7.6#/sq in. ...