

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. that might be before high school). i also like how one linked explanation sits near two pieces of slop and is wrong





their practical skills are weak, and they won’t survive the winter (because they don’t know how to make jam)
but frame the same physics in terms of what makes steam turbine spin, and they’ll pretend to get it but won’t apply it anywhere else. the longer you look the worse it gets. it’s like they have never watched how it’s made as kids