I think I understand it now. Take a droplet of black organic goop and put it in oil. Turn on an electric field. When the field is strong enough, the droplet will start to spin!
Here's why. Even though the oil doesn't conduct electricity well, a few electrons will move through the oil, pushed by the electric field. They'll land on top of the droplet and stick there - because we've chosen a kind of goop that's *very* hard for electrons to move through.
A few more electrons will land on one side than the other, by chance. The electric field will keep pushing them down, so they will start to turn the droplet. When they reach the bottom of the droplet, some will fall off and continue moving through the oil. And this process will continue, making the droplet turn faster and faster.
This effect is called Quincke rotation.
nprofile1qy2hwumn8ghj7un9d3shjtnddaehgu3wwp6kyqpqx40xlna0p2pulumyf5vuck2xae767zk65u62pwyu5apd330hnnwqzx40e0 (nprofile…40e0) helped me think of a nice analogy. Suppose you have a waterwheel in a torrential rain. If a bit more rain lands on one side than another, it will start to turn the waterwheel. And once the wheel starts turning, the rain can make it turn faster!
https://www.youtube.com/watch?v=Z6rGIfDujdI
John Carlos Baez /
npub17u…8pd6m
2025-05-12 14:14:01
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npub17u6xav5rjq4d48fpcyy6j05rz2xelp7clnl8ptvpnval9tvmectqp8pd6mPublished at
2025-05-12 14:14:01Event JSON
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"content": "I think I understand it now. Take a droplet of black organic goop and put it in oil. Turn on an electric field. When the field is strong enough, the droplet will start to spin! \n\nHere's why. Even though the oil doesn't conduct electricity well, a few electrons will move through the oil, pushed by the electric field. They'll land on top of the droplet and stick there - because we've chosen a kind of goop that's *very* hard for electrons to move through. \n\nA few more electrons will land on one side than the other, by chance. The electric field will keep pushing them down, so they will start to turn the droplet. When they reach the bottom of the droplet, some will fall off and continue moving through the oil. And this process will continue, making the droplet turn faster and faster.\n\nThis effect is called Quincke rotation.\n\nnostr:nprofile1qy2hwumn8ghj7un9d3shjtnddaehgu3wwp6kyqpqx40xlna0p2pulumyf5vuck2xae767zk65u62pwyu5apd330hnnwqzx40e0 helped me think of a nice analogy. Suppose you have a waterwheel in a torrential rain. If a bit more rain lands on one side than another, it will start to turn the waterwheel. And once the wheel starts turning, the rain can make it turn faster!\n\nhttps://www.youtube.com/watch?v=Z6rGIfDujdI",
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