• chonglibloodsport@lemmy.world
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    22 days ago

    For those playing at home, try this:

    Heat up a frying pan on low heat and throw some water in there. It sizzles and bubbles weakly but evaporates quite quickly.

    Now heat up the pan over medium-high heat. Throw water in there and watch it turn into little marbles that dance around the pan. It seems much more violent but notice that the water marbles last way longer because they’re actually floating on a cushion of steam. This is also why they seem to fly around pan so rapidly: the steam cushion removes almost all of the friction.

    This is called the Leidenfrost effect. Very high temperature frying pans actually conduct heat into the water more slowly than lower temperature ones because the steam cushion acts as an insulator.

    Well it turns out if you put your hand in molten metal the same thing happens! The moisture on your skin flashes to steam and creates a barrier which slows down the conduction of heat into your skin. Of course, if you fall into molten metal you may not be able to get out. The Leidenfrost effect also doesn’t do anything to protect you from the intense thermal radiation being emitted by the molten metal!

    Funnily enough, this also happens if you pour some liquid nitrogen into your hands. It dances around just like the water does in the hot frying pan. Your skin is like a hot frying pan compared to liquid nitrogen and the nitrogen gas produced is like steam in this case.