Post #2747512

But anyways - why is there a vacuum in the jar? To preserve the jam? Isn’t jam a preserve? Like, I thought the whole raison d’etre of jam was as a way to make fruit keep, unrefrigerated, through the winter? Why must we preserve the preserve? Quis custodiet ipsos custodes? this is “fucking magnets, how do they work” translated to rationalist, except that explaining magnets involves quantum mechanics and explaining jam jars involves high school physics (saturated vapor pressure vs temperature)