quantum quack Posted July 17, 2005 Report Posted July 17, 2005 I am not sure how to start this discussion on this observation but I'll give it a go any way....IN essence it is a physical representation of a deeper philosophical question about oneness yet simultaneously maintaining separateness, however I put it forward as a question of physics in this post. Basically if we take pressure or the absence of pressure as an example.Say for example we have 2 cubic 1 meter vacuum chambers and we vacate them to say, -10 units of pressure relative to the pressure outside the chamber.We now add these two volumes of space together and we still have -10 units of pressure. However if we invert the scenario and make two chambers of +10 units of pressure, when we add them [the two volumes of space] together what do we have as the sum of both chambers? My guess is we have +20 units so in one case two volumes of vacuum equal the same value in pressure where as two volumes of pressure equals the sum of both volumes [addition] Now if we consider that both the negative and positive volumes are essentially the same volume [ and pressure ] and only seen from different perspectives we have a seemingly paradoxical result. When looking at it from an ambient pressure perspective we have 1+1=1 and when looking at it from an ambient vacuum, perspective we have 1+1=2. Thus this can be logically exteded to mean philosophically 0+0 = 0 but also 0+0 = 1 simultaneously. Does this make any sense at all? Quote
EWright Posted July 17, 2005 Report Posted July 17, 2005 I am not sure how to start this discussion on this observation but I'll give it a go any way....IN essence it is a physical representation of a deeper philosophical question about oneness yet simultaneously maintaining separateness, however I put it forward as a question of physics in this post. Basically if we take pressure or the absence of pressure as an example.Say for example we have 2 cubic 1 meter vacuum chambers and we vacate them to say, -10 units of pressure relative to the pressure outside the chamber.We now add these two volumes of space together and we still have -10 units of pressure. However if we invert the scenario and make two chambers of +10 units of pressure, when we add them [the two volumes of space] together what do we have as the sum of both chambers? My guess is we have +20 units so in one case two volumes of vacuum equal the same value in pressure where as two volumes of pressure equals the sum of both volumes [addition] Now if we consider that both the negative and positive volumes are essentially the same volume [ and pressure ] and only seen from different perspectives we have a seemingly paradoxical result. When looking at it from a pressure perspective we have 1+1=1 and when looking at it from a vacuum, perspective we have 1+1=2. Thus this can be logically exteded to mean philosophically 0+0 = 0 but also 0+0 = 1 simultaneously. Does this make any sense at all? This is not an area I have ever focused on or taken interest in, but logically ti seems to me that you are mistaken. Try looking at it as a ratio/proportion issue. In both cases your ratio remins 1:1. When you are adding the positive relationships together, your adding the same amount of volume as you are pressure, so the ratio remains the same per unit of measurement. Quote
quantum quack Posted July 17, 2005 Author Report Posted July 17, 2005 This is not an area I have ever focused on or taken interest in, but logically ti seems to me that you are mistaken. Try looking at it as a ratio/proportion issue. In both cases your ratio remins 1:1. When you are adding the positive relationships together, your adding the same amount of volume as you are pressure, so the ratio remains the same per unit of measurement. let me try another approach..... If I take a container of 10 psi and squeeze that volume into a similar container with 10 psi I have a result of 20 psi....yes? Can we agree with this? [the way a pump functions] If I take a container with -10 psi and squeeze that volume into a similar contaiiner with -10 psi I would expect a result of only -10 psi...would this be correct? Can we agree with this? btw thanks for your response :) Quote
quantum quack Posted July 17, 2005 Author Report Posted July 17, 2005 just to addsay we use the followingwherev = volume of vacuum and p = volume of pressure 1v + 1v = 1v1p + 1p = 2p Where pressure is a relative concept Quote
EWright Posted July 17, 2005 Report Posted July 17, 2005 let me try another approach..... If I take a container of 10 psi and squeeze that volume into a similar container with 10 psi I have a result of 20 psi....yes? Can we agree with this? [the way a pump functions] If I take a container with -10 psi and squeeze that volume into a similar contaiiner with -10 psi I would expect a result of only -10 psi...would this be correct? Can we agree with this? btw thanks for your response :) :xx: No, you would have -20psi in the container smaller container. Consider two glasses upside down in a container of water with an inch of air caught in each one. If you release the air from one glass into the other you will now have two inches of air (negative pressure in this case) in the second glass. It remains negatively proportional to its positive counterpart. Quote
EWright Posted July 17, 2005 Report Posted July 17, 2005 just to addsay we use the followingwherev = volume of vacuum and p = volume of pressure 1v + 1v = 1v1p + 1p = 2p Where pressure is a relative concept You will then have two units of pressure (be it negative or positive) in one unit of volume. You actually have 2v - 1v = 1v and 1p + 1p = 2p. Holy cow, I think I actually just spoke physics! :) Quote
quantum quack Posted July 17, 2005 Author Report Posted July 17, 2005 You will then have two units of pressure (be it negative or positive) in one unit of volume. You actually have 2v - 1v = 1v and 1p + 1p = 2p. Holy cow, I think I actually just spoke physics! :)it is true if you are talkking about the number of volumes. But we are talking about the value of pressure when combining volumes.....i think :) Quote
EWright Posted July 17, 2005 Report Posted July 17, 2005 it is true if you are talkking about the number of volumes. But we are talking about the value of pressure when combining volumes.....i think :) :) I thought so too. :) I think I'm still correct though. The pressure volumes would be combined either negatively or positively, no? :) Quote
quantum quack Posted July 17, 2005 Author Report Posted July 17, 2005 :) I thought so too. :) I think I'm still correct though. The pressure volumes would be combined either negatively or positively, no? :) I guess it comes down to teh basic question of what happens if you add -10 units of pressure to -10 units of pressure? does it equal -20 units or -10 units? keeping in mind that adding a volume of vacuum does not increase the vacuum unless the negative pressure is greater [lesser] than the original pressure.....hmmmmm :)this is my premise10 v + 13v = 13v it would only take 13 v to combine the two volumes however 10 p + 13p = 23pit would tke 23 p to combine the two volumes Quote
EWright Posted July 17, 2005 Report Posted July 17, 2005 I guess it comes down to teh basic question of what happens if you add -10 units of pressure to -10 units of pressure? does it equal -20 units or -10 units? keeping in mind that adding a volume of vacuum does not increase the vacuum unless the negative pressure is greater [lesser] than the original pressure.....hmmmmm :)this is my premise10 v + 13v = 13v it would only take 13 v to combine the two volumes however 10 p + 13p = 23pit would tke 23 p to combine the two volumes Going back to my upside down glasses of water scenario, you do get increased negative pressure, which is doubled relative to what it was and the corresponding equal amount of positive pressure is displaced by the new negative pressure. Right? :) Quote
Erasmus00 Posted July 17, 2005 Report Posted July 17, 2005 Start with an ideal gas equation of state PV=NkT. Or, P=NkT/V. In your example, you take two containers, each identical, so same volume, same number of gas molecules N. Now, "adding" the two boxes, I'm assuming, means putting them side by side and removing the connecting wall. This has the effect of doubling N and V, which from the equation for pressure we see this has no effect. Because this argument works for absolute pressure, it applies to both your negative and positive pressure cases. -Will Quote
EWright Posted July 17, 2005 Report Posted July 17, 2005 Start with an ideal gas equation of state PV=NkT. Or, P=NkT/V. In your example, you take two containers, each identical, so same volume, same number of gas molecules N. Now, "adding" the two boxes, I'm assuming, means putting them side by side and removing the connecting wall. This has the effect of doubling N and V, which from the equation for pressure we see this has no effect. Because this argument works for absolute pressure, it applies to both your negative and positive pressure cases. -Will Pretty sure I said the same thing in plain ol' english. See, we don't need no stinkin' formulas! :xx: Quote
Boerseun Posted July 17, 2005 Report Posted July 17, 2005 I think there's a fundamental error in your reasoning. There is no intrinsic difference between a container with a pressure of 10psi and a container with a pressure of -10psi. Remeber, you can't have a negative gas pressure. It goes down to zero for vacuum, and that's it. Everything is above zero as far a gas pressure is concerned. Relating it to outside pressure, sure - you can have a negative in relation to something else - but that would imply that the outside pressure has anything to do with your experiment. Which it doesn't, so negative numbers here will just confuse.So - you example should be a container with 10psi and a container with 1psi (or some similar values). In which case, 10+10 will be 20 and 1+1 will be 2, they'll act in exactly the same fashion. Quote
quantum quack Posted July 17, 2005 Author Report Posted July 17, 2005 I think there's a fundamental error in your reasoning. There is no intrinsic difference between a container with a pressure of 10psi and a container with a pressure of -10psi. Remeber, you can't have a negative gas pressure. It goes down to zero for vacuum, and that's it. Everything is above zero as far a gas pressure is concerned. Relating it to outside pressure, sure - you can have a negative in relation to something else - but that would imply that the outside pressure has anything to do with your experiment. Which it doesn't, so negative numbers here will just confuse.So - you example should be a container with 10psi and a container with 1psi (or some similar values). In which case, 10+10 will be 20 and 1+1 will be 2, they'll act in exactly the same fashion.I do see what you are saying however your post prompts the question what happens then if you add a volume of zero pressure to a volume of zero pressure? What pressure woudl be the result? obviously I am stating the 0+0 = 0 position....however if you add a volume of gas at 10 psi to a volume of gas at 10 psi and maintain the same volume you will have 20 psi.If I add a zero pressure volume to a zero pressure volume I will still get zero pressure..... BTW I agree my original reasoning has many problems.......... Quote
Boerseun Posted July 17, 2005 Report Posted July 17, 2005 I do see what you are saying however your post prompts the question what happens then if you add a volume of zero pressure to a volume of zero pressure? What pressure woudl be the result? obviously I am stating the 0+0 = 0 position....however if you add a volume of gas at 10 psi to a volume of gas at 10 psi and maintain the same volume you will have 20 psi.If I add a zero pressure volume to a zero pressure volume I will still get zero pressure..... BTW I agree my original reasoning has many problems..........Yes, the volume of "nothing" doesn't matter - there's still nothing. I fail to see the issue here if we stick to positive values? Quote
quantum quack Posted July 17, 2005 Author Report Posted July 17, 2005 Yes, the volume of "nothing" doesn't matter - there's still nothing. I fail to see the issue here if we stick to positive values? It maybe that teh example we have developed is too simple.of course 0+0 =0 But if that zero pressure is given the value of 1vac we also can derive 1+1 =1vacPhilosophically it is only the application of pressure that keeps us separate. If we apply no pressure we are one......[sort of thing] For example is I attempt to change your mind on this issue I am applying pressure and that pressure is additive however if I cease to apply pressure or we are in agreement we are one on the issue thus zero pressure exists. The pressure to change is neutralised once that change has occured.Any way this is now philosophy so I'll leave it at that, I just thought you deserved an explanation to this threads topic. Quote
C1ay Posted July 17, 2005 Report Posted July 17, 2005 let me try another approach..... If I take a container of 10 psi and squeeze that volume into a similar container with 10 psi I have a result of 20 psi....yes? Can we agree with this? [the way a pump functions] If I take a container with -10 psi and squeeze that volume into a similar contaiiner with -10 psi I would expect a result of only -10 psi...would this be correct? Can we agree with this?No. A container at -10psi is not totally evacuated as is actually at around 4.5 PSIA (pounds per square inch absolute). Taking the volume of 2 such containers and adding them together in one container would result in a pressure of 9 PSIA or ~ -5.5 PSI. Quote
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