So you're saying that it doesn't work by the rules of magic because of the rules of magic? Sorry if I'm being snarky, but the answers I'm seeing don't make any sense. I'm not invoking physics beyond what the rules call for: That objects have weight and size. That the bag has a hard limit on both isn't physics, it's just the rules for a magic item.
People seem to be saying that you can't do something stupid thoughtlessly or by accident, only on purpose. I guess I'll have to write it off to "Different DMs, different approached to the rules".
Now, why would water rush in? Because there's gravity outside the bag, and things fall. And while I believe that there's gravity inside the bag as well, even if there wasn't the water would still be pushed by the water outside, where gravity still applies. (There are spells to handle water pressure, and it's mentioned in the Planar Handbook, Manual of the Planes and Stormwrack, so I'm only talking about the physics of the game as already defined in the rules.)
So what happens to the weight of the air in the Bag. Note that the same amount of air is stored in each bag, despite their markedly differing sizes, as a living being can breathe for the same amount of time in each bag. What are the physics for that?
Oryan correctly pointed out that the rules don't say things fall out if you turn the bag upside down, only if you turn it inside out. The Bag itself is an interface to a nondimensional space, so there is no reason gravity would remain the same past that threshold.
It takes a round - 6 seconds - to go through 250 cubic feet of space (just over 7' x 7' x 10' - that's considerably bigger than a closet, more like a walk-in closet) and haul out something of the 1,500 lbs therein from the bottom. Does that sound like ordinary physics?
Is there some argument to say otherwise? (Other than, "Because we're in love with the idea"?)
I'm actually serious aboot that question, by the way. It isn't rhetorical or argumemtative (though I could see how someone mighttake it that way). Is there anyplace in the rules that says there's no gravity inside a Bag of Holding? I freely admit that I don't own all the books, and certainly haven't memorized even the ones I have. There might be mention of such a thing that I don't know about.
I don't believe it says one way or the other. If everything is at the bottom of the bag (the point furthest from the aperture), how do we get items out so quickly? The actual dimensions of the interior are not, to my knowledge, every addressed, only that it is bigger inside, and here is how much it can hold.
Where does it say that the bag can be accidentally overfilled, rather than appearing quite full, requiring the user to force another object in (and thereby rupturing the bag)?
The point is that the rules don't go into that level of detail, so one must make suppositions regarding how the magic will work. For me, it is not so serious an issue that I find it imperative to create a ruling that disadvantages the characters should they happen to open a bag of holding underwater.
What percentage of PC's have hauled a Haversack or Bag of Holding into a Rope Trick? What hazards occur. We know taking an extradimensional space into another extradimensional space is "hazardous" from the spell, but we don't know how it is hazardous. How many PC groups hang their Haversacks and Bags of Holding on a tree outside the Rope Trick entry point?
I don't think you can tip a bag of holding and pour the contents out. I think you have to turn the bag inside out to "dump" the contents out?
If so, then wouldn't the reverse work the same? You can pour things in the bag?
I still see the bag of holding working like a portal or gate spell. Portals leading to the Elemental Plane of Water don't cause water to rush out and flood the material plane. Real flames and extreme heat don't flicker out of a portal leading to the Elemental Plane of Fire. The contents to the plane on the other side of the portal are contained. Why wouldn't that be the same for the plane that exists inside a bag of holding? The opening is just a portal to another plane.
Again, this seems a reasonable interpretation - the Bag is an aperture to a different dimension.
Actually, according to the SRD, pulling an item is a move action unless the bag holds more than a backpack would (in which case it's a full-round action). Amusingly, 3e neglects to define just how much a backpack holds.
From a websearch:
The 3.0 PHB had the limits for all of these.
Backpack weight=2lbs holds 40lbs
Large Sack weight = 1lbs holds 60lbs
Small Sack weight = 0.5lbs holds 30 lbs
Large Belt Pouch weight = 0.5lbs holds 10lbs (fuzzy memory on this one)
Small Belt Pouch weight = nil holds 1lbs
Pack Saddles = as much as the mount can carry
Saddlebags weight = ?? holds 30lbs each (in pairs, but fuzzy memory on this one too).
So it was in 3rd, but somehow vanished in 3.5 and stayed vanished in Pathfinder, right through Ultimate Equipment.
