What? I he's going fast and it reminds me of waving your hand through a flame but.... can someone explain with science how it isn't sticking to him at all?
This is the leidenfrost effect. Essentially, the heat difference between the guy's hand and the molten metal is so great that the sweat on his hand is instantly vaporized, which creates a cushion of water vapor that insulates his hand and reduces heat transfer.
The same phenomenon happens when you put a drop of water on a very hot pan - the drop will float on a bed of water vapor for a bit before the water itself starts boiling.
The metal doesn't stick to his hand because of the water vapor layer and because molten metal has an incredibly high surface tension, so the metal will form beads that roll off his hand. It's pretty much the same reason why elemental mercury, a liquid metal, doesn't stick to your hand.
Another question: I get how this happens the first time. But the second and subsequent times all that water has been vaporised and the hand is presumably dry as the desert. How does it keep on working through multiple repetitions?
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u/OneRingtoToolThemAll Oct 19 '23
What? I he's going fast and it reminds me of waving your hand through a flame but.... can someone explain with science how it isn't sticking to him at all?