Thank you! This gave me an excuse to use the online OED to look up something. And I found this handy factiod: The strength of the interplanetary magnetic field near the Earth is on average 5 nanoteslas.
Every so often in the science news one reads about some lab that's built a gigantor magnet with a field that's, like, 8 Tesla, which is just terrifyingly strong.
Well, the primary cause for this effect is high magnetism scientists with wayyy too much free time. The secondary cause is magnetisation of just enough blood cells.
Stick anything in a magnetic field and diamagnetism (which is the opposite polarity from ferromagnetism) generates a repulsive force. If your magnetic field is big enough (and pointing upward), you can levitate the object.
I'm pretty sure that's how it works, anyway. IIRC, liquid oxygen has a higher diamagnetic, um, thingy (moment?) than most stuff, so you can make a blob of LOX float in between big-but-not-ludicrous magnets pretty easily.
Many years ago I was taking a T-ride with a friend and the subject turned to spherical swimming pools in free-fall, and whether they would be practical. I forget exactly what aspect of the question brought us to BOTECs on volume, but I shamefacedly admitted I'd forgotten the formula for the volume of a hollow sphere, and was trying to rederive it. And the guy across the aisle leaned over and recited it for me. I was appreciative; my friend was bemused.
I'm never entirely sure if I should say these sorts of things when people are talking about them around me. Though some time ago I did give a 10-minute explanation of the Human Genome Project to someone who was really, really getting it wrong with someone he was talking about it with at an airport.
Many years ago I overheard one woman say to another at a museum exhibit, regarding a note about the composition of some star or another, skeptically, "how could they possibly know that?" and delivered an impromptu lecture on spectroscopy and how cool it is that they can, in fact, know that. I never did know whether they appreciated it, but I enjoyed it.
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dr_tectonic
no subject
Date: 2004-10-08 02:09 pm (UTC)no subject
Date: 2004-10-08 03:42 pm (UTC)Every so often in the science news one reads about some lab that's built a gigantor magnet with a field that's, like, 8 Tesla, which is just terrifyingly strong.
no subject
Date: 2004-10-08 04:22 pm (UTC)no subject
Date: 2004-10-09 07:47 pm (UTC)How does that work? I don't get it. Of course, I don't even remember how the levitating superconductor works.
no subject
Date: 2004-10-10 12:16 pm (UTC)no subject
Date: 2004-10-11 10:06 am (UTC)Stick anything in a magnetic field and diamagnetism (which is the opposite polarity from ferromagnetism) generates a repulsive force. If your magnetic field is big enough (and pointing upward), you can levitate the object.
I'm pretty sure that's how it works, anyway. IIRC, liquid oxygen has a higher diamagnetic, um, thingy (moment?) than most stuff, so you can make a blob of LOX float in between big-but-not-ludicrous magnets pretty easily.
no subject
Date: 2004-10-09 04:09 pm (UTC)no subject
Date: 2004-10-10 06:52 am (UTC)no subject
Date: 2004-10-10 04:46 pm (UTC)