John Carlos Baez on Nostr: SELF-PROPELLING PARTICLES Take a tiny rod with one half made of gold and the other ...
SELF-PROPELLING PARTICLES
Take a tiny rod with one half made of gold and the other made of platinum. Put it in hydrogen peroxide. It will start to move!
The platinum end catalyzes a reaction where hydrogen peroxide turns into water and oxygen, and this pushes the rod along. It can move 10 times its own length every second - comparable to the speed of a bacterium with flagellae!
This experiment was first done in 2004. By now people have studied a wide variety of self-propelling particles:
https://en.wikipedia.org/wiki/Self-propelled_particlesMany are Janus particles, with two sides made of different materials:
https://en.wikipedia.org/wiki/Janus_particlesThe term 'Janus particle' was invented by Leonard Wibberley in his 1962 novel The Mouse on the Moon as the name for a device for space travel. The term was first used in science in 1988, to describe tiny glass spheres with a coating that makes one hemisphere attract water and the other repel it. These Janus particles naturally orient themselves at the surface between water and oil.
Published at
2025-05-17 09:16:43 UTCEvent JSON
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"content": "SELF-PROPELLING PARTICLES\n\nTake a tiny rod with one half made of gold and the other made of platinum. Put it in hydrogen peroxide. It will start to move!\n\nThe platinum end catalyzes a reaction where hydrogen peroxide turns into water and oxygen, and this pushes the rod along. It can move 10 times its own length every second - comparable to the speed of a bacterium with flagellae!\n\nThis experiment was first done in 2004. By now people have studied a wide variety of self-propelling particles:\n\nhttps://en.wikipedia.org/wiki/Self-propelled_particles\n\nMany are Janus particles, with two sides made of different materials:\n\nhttps://en.wikipedia.org/wiki/Janus_particles\n\nThe term 'Janus particle' was invented by Leonard Wibberley in his 1962 novel The Mouse on the Moon as the name for a device for space travel. The term was first used in science in 1988, to describe tiny glass spheres with a coating that makes one hemisphere attract water and the other repel it. These Janus particles naturally orient themselves at the surface between water and oil.\nhttps://media.mathstodon.xyz/media_attachments/files/114/522/331/076/190/800/original/5a230f726d1c75f8.jpg\n",
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