Ok, I’ve seen two movies in recent weeks in which the plot involves long-buried 19th century American ships in remote places they shouldn’t be. The flicks were Sahara and National Treasure. In both cases, the 150+ year old gunpowder on board, despite being in an inhospitable environment and all, was not only still present, unmixed with contaminants, and chemically unchanged, it was still extremely explosive. The concatenation of these points is kinda like the thread I posted not long ago about coincidences ion the movies. But is this? Or are we entering an era when people know (or care) so little about things like the stability of gunpowder that they can accept this kinda thing?
(Of course, movies with long-dormant but still viable gunpowder aren’t new – look at A Journey to the Center of the Earth. But Verne never wrote that bit of idiocy – he’d have known better. And I’m still annoyed at centuries-old booby traps that still work perfectly, a la Indiana Jones or The Goonies. At least Carl Barks had people tending his booby traps.)
I always had the impression that the Hovitos people tended to the traps that bedevilled Indianna Jones.
I was watching the remake of Flight of the Pheonix last night, and I did get breifly annoyed when a fuel barrel explodes.
And I also noticed the same about National Treasure, RE: The gunpowder. It’s annoying and unrealistic, but it’s also a hollywood action movie staple. Anything that looks like it could explode will explode for extra dramatic effect.
He could have asked them, if only he spoke Hovitos.
People also think, as a result of the movies, that hand grenades explode with a huge blast and gouts of flame. There must be something about celluloid that makes explosives stable for long periods and downright nuclear in their effects!! 
Well, don’t forget the season finale of ** Lost **. Which included a ship where it shouldn’t have been, loaded with dynamite which shouldn’t have existed when the ship was sailing (based on the ship apparently being a slaver). At least in Lost, the explosives had deteriorated and become dangerously unstable.
So that makes three.
Still, is there anything about gunpowder in a sealed cask that would cause it to deteriorate over time, assuming that humidity can’t get to it?
Actually, blackpowder remains explosive for a very, very long time provided it is kept dry. You don’t get much drier than the Sahara…
Hmm…black powder contains a lot of salts, which are notoriously good at sucking out whatever moisture there is in the atmosphere. I have some British ammunition from the 1860s/1870s (Snyder and Martini rounds), in which the powder seems to have become pretty solid. I wouldn’t want to cut them open and wave a match at them (both for safety reasons, and because these are scarce collector’s items!)
I know that there are hundreds of bags of solidified WWI black powder charges sitting under a parking lot (!) at Vimy Ridge Memorial in France, part of a mining charge under then-German front line trenches that was never detonated. These were judged to be stable enough to leave in situ, but too unstable to start moving out (since that would entail drilling into the now bricklike solidified explosive, plus some of the bags may have had other more complex compounds in them, such as lyddite, ammonal, etc.)
Interesting.
Cold air can’t hold much moisture, so the casks on the ship in National Treasure would probably have stayed pretty dry. I doubt that the ship would have stayed in one piece, however. From what I’ve read, ships trapped in ice tend to get crushed fairly quickly.
Yeah, but I can see it getrting mixed with sand and dry salt pretty easy. Plus the interior of the damned vessel would get filled with the sand, too.
That’s what I found most unrealistic about National Treasure (apart from the hot lady falling for Nick Cage) was the pristine condition of the ship in the ice.
Ships trapped in ice should get crushed as the ice floats about, right? But even if they didn’t, would the hold remain dry? Wooden ships were not watertight when built, one would think that over 2 centuries, the old oakum and pitch or whatever would have lost its effectiveness in the brittle conditions and the ship would have filled with water.