Comment on My ravioli bowl won't unstick. Took about an hour of prying, and still I couldn't unstick the plate.
FreeBeard@slrpnk.net 2 days agoIt’s delta p and not fraction p. The difference between ambient pressure and inner pressure (at least zero) is always smaller than ambient pressure. Delta p is therefore limited.
Earflap@reddthat.com 2 days ago
OK and? A difference of just 2 psi means that a bowl with diameter 4 in. (complete guess) is being held in place with ((4π)=12.562)= 25 lbs of force distributed evenly across the surface of the plate.
A bigger bowl or greater suction changes these numbers dramatically. 2 psi on a 6 in. bowl is held in place with 37 lbs of force. 4 psi on a 6 in. bowl is held in place with 75 lbs of force.
Sure its “limited” in that there can only be a 14.7 pressure difference, but that doesn’t mean anything in terms of “this is really hard to undo”.
And if there’s oil or food or something sealing the gap between bowl and plate… fugheddaboudit.
FreeBeard@slrpnk.net 2 days ago
I sadly don’t understand these units and your point is drained in it. The point I want to make is that the “force” of vacuum is limited by the difference of pressures.
You say it changes “drasticly” with area or suction but that is untrue. It changes linearly with area (not drastically) and pressure difference has a maximum. The maximum is defined by the pressure of the vacuum(=0) and the pressure of the ambient air (1 arm). Both are constant so the maximum is constant and actually not that big.
Earflap@reddthat.com 2 days ago
I could change all the units to potatoes and wombats and my point would still be valid.