Author: **joannaardway** » Fri Feb 02, 2007 5:54 am

There is a set pressure per pump (assuming no leakage), but I wouldn't use that to calculate how many pumps it would take.

It gets harder to pump, but the pressure still increases by the same amount per pump.

Take the ideal gas equation:

pV = nRt

P is pressure, v is volume, n is number of moles of gas (proportional to the number of molecules of gas), R is the gas constant, and t is the absolute temperature.

V,R and t are considered constant for this. (In truth, t will rise slightly, but the effect is small).

To increase the amount of gas in the chamber by a set amount, you add n moles of gas with a pump. This quantity is the same for each pump, as the pump is always the same volume, and at the same pressure (14.7 psi from the atmosphere) - so the same number of molecules are present.

Given that v, r, and t aren't changing, the only value that changes is the pressure. As n is changing by the same amount each time, P must do the same in exact proportion.

So there is a set pressure per pump, but taking into account leakage, then your actual pressure will be different to your calculated pressure.

Novacastrian: How about use whatever the heck you can get your hands on?

frankrede: Well then I guess it won't matter when you decide to drink bleach because your out of kool-aid.

...I'm sorry, but that made my year.