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Thomas comments on Magnetic rings (the most mediocre superpower) A review. - Less Wrong Discussion

26 Post author: Elo 30 July 2015 01:23PM

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Comment author: Thomas 31 July 2015 11:02:43AM *  1 point [-]
Comment author: bbleeker 01 August 2015 07:19:38AM 1 point [-]

Interesting! It's not the same thing as what happens when a magnet is attracted to a ferrous metal, though. As they explain in the comments, the magnet falling through the pipe creates a current in the copper, making it an electromagnet. That should work with *any * metal, also gold; but it identifies a metal only as a metal, you wouldn't be able to tell which one (maybe if you made sufficiently precise measurements you could tell by the strength of the magnetic field, but we're talking about someone wearing a magnetic ring, not about lab setups). You couldn't use it to tell if some ore contained gold.

But now I'm wondering what would happen if you drop a piece of non-ferrous metal through a magnetic pipe... A ring is a very short pipe though; to see any effects you'd probably have to film it and play it in slow motion, so it wouldn't be very useful for prospecting either.

Comment author: Thomas 01 August 2015 08:26:53AM *  2 points [-]

This is the basis for metal detectors, anyway. Golden pieces should have been detectable (and movable) by magnets, provided there is magnetic field, strong enough.

Some calculations just how strong and what the whole structure should have been - are necessary. But it should have been possible to make some magnetic gadget for gold "panning".

Comment author: Lumifer 01 August 2015 11:48:05PM 1 point [-]

it should have been possible to make some magnetic gadget for gold "panning".

Provided that gold is the only metal in your ore. That is usually not the case.

Comment author: Thomas 02 August 2015 07:21:38AM 1 point [-]

You are wrong here. Wikipedia has this to say:

Gold occurs principally as a native metal, usually alloyed to a greater or lesser extent with silver (as electrum), or sometimes with mercury (as an amalgam). Native gold can occur as sizeable nuggets, as fine grains or flakes in alluvial deposits, or as grains or microscopic particles embedded in other rocks.

See.

Comment author: Elo 01 August 2015 09:04:21AM 1 point [-]

To form eddy currents you need enough metal in which to form them. If you have ever seen the experiment with the pipe above - vs the same with a slit in the pipe to lower the number of currents that can form - there is a considerable loss of currents forming.

Compared to natural ores - to be able to produce currents that can be felt is going to be difficult.

I have a few iron ore rocks that midly stick the the rings. but they barely support their own mass against gravity.

Comment author: Thomas 01 August 2015 09:52:38AM 0 points [-]

Compared to natural ores

Gold comes mostly in elementary gold particles, nuggets. That's why it's probably possible to fish it this way. (Perhaps a few people do just that and don't talk too much about it from obvious reasons.)

Comment author: Elo 01 August 2015 10:02:48AM 0 points [-]

Its possible. Seems like too much effort to get anything of worth.