# Does liquid metal attract to a magnet? **URL:** \ **Category:** Factual Questions\ **Created:** [February 23, 2004, 11:27pm UTC](https://boards.straightdope.com/t/does-liquid-metal-attract-to-a-magnet/230775 "2004-02-23T23:27:56Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![Bret](https://avatars.discourse-cdn.com/v4/letter/b/8baadc/32.png) [@Bret](https://boards.straightdope.com/u/Bret)\ **Post date:** [February 23, 2004, 11:27pm UTC](https://boards.straightdope.com/t/does-liquid-metal-attract-to-a-magnet/230775/1 "2004-02-23T23:27:56Z")
Does liquid metal attract to a magnet? ---
**Author:** ![Tentacle\_Monster](https://avatars.discourse-cdn.com/v4/letter/t/ba9def/32.png) [@Tentacle\_Monster](https://boards.straightdope.com/u/Tentacle_Monster)\ **Post date:** [February 23, 2004, 11:55pm UTC](https://boards.straightdope.com/t/does-liquid-metal-attract-to-a-magnet/230775/2 "2004-02-23T23:55:17Z")
I don’t know from experience, but I can hypothesize. Magnets stick to each other because all (or a majority, anyway) of the atoms in a metal are aligned in the same direction. (Some) metals become magnets when exposed to a magnetic field, causing them to become attracted to each other If a metal is hot enough to be in liquid form, all of the atoms are too busy jumping around to align themselves to the magnetic field. Perhaps if a liquid metal were exposed to a very powerful magnet, the atoms in the liquid would align themselves and turn the liquid into a solid. That’s pure speculation, however. What I know is that magnets, if heated to a sufficient degree, lose their magnetic properties. ---
**Author:** ![Flying\_Monk](https://avatars.discourse-cdn.com/v4/letter/f/48db29/32.png) [@Flying\_Monk](https://boards.straightdope.com/u/Flying_Monk)\ **Post date:** [February 24, 2004, 12:26am UTC](https://boards.straightdope.com/t/does-liquid-metal-attract-to-a-magnet/230775/3 "2004-02-24T00:26:16Z")
AFAIK, only ferrous metals are ferromagnetic, and ferrous metals are solid at room temperature. I know that magnets lose their magnetic field if they get hot enough, so I’d think that molten metal isn’t ferromagnetic. I don’t think sodium or mercury are ferrous, so my guess is the answer is no. ---
**Author:** ![Thaumaturge](https://avatars.discourse-cdn.com/v4/letter/t/858c86/32.png) [@Thaumaturge](https://boards.straightdope.com/u/Thaumaturge)\ **Post date:** [February 24, 2004, 12:33am UTC](https://boards.straightdope.com/t/does-liquid-metal-attract-to-a-magnet/230775/4 "2004-02-24T00:33:07Z")
It is theorized that liquid metalic hydrogen would be magnetic IIRC. Unfortunately, it requires extreme pressures to come into being. ---
**Author:** ![Doc\_Nickel](https://avatars.discourse-cdn.com/v4/letter/d/5fc32e/32.png) [@Doc\_Nickel](https://boards.straightdope.com/u/Doc_Nickel)\ **Post date:** [February 24, 2004, 1:53am UTC](https://boards.straightdope.com/t/does-liquid-metal-attract-to-a-magnet/230775/5 "2004-02-24T01:53:15Z")
Actually, it’s quite common for blacksmiths and others heat-treating or tempering small parts, to use a small magnet to determine the steels “critical temperature” for quenching. Basically, once a magnet will no longer stick, it’s hot enough and ready for your quenching/tempering procedure. So no, since only iron and steel are magnetic (or are attracted to magnets, anyway) and both iron and steel lose that attraction at tempratures well below molten, “liquid metals” are not magnetic. ---
**Author:** ![umop\_ap\_sdn](https://avatars.discourse-cdn.com/v4/letter/u/dbc845/32.png) [@umop\_ap\_sdn](https://boards.straightdope.com/u/umop_ap_sdn)\ **Post date:** [February 24, 2004, 2:00am UTC](https://boards.straightdope.com/t/does-liquid-metal-attract-to-a-magnet/230775/6 "2004-02-24T02:00:19Z")
For the record, cobalt, nickel (Doc, I’m surprised at you!) and gadolinium are also ferromagnetic. But I doubt any of them keep their magnetism if heated, seeing as iron does not. IIRC there is one known ferromagnetic liquid. It isn’t a pure substance but rather a compound or solution (ferrate?). All I know is it’s black and can be used to make a nice moving exhibit in a science museum. ---
**Author:** ![Ale](https://avatars.discourse-cdn.com/v4/letter/a/f19dbf/32.png) [@Ale](https://boards.straightdope.com/u/Ale)\ **Post date:** [February 24, 2004, 2:39am UTC](https://boards.straightdope.com/t/does-liquid-metal-attract-to-a-magnet/230775/7 "2004-02-24T02:39:00Z")
> [@cityboy916](#): > > IIRC there is one known ferromagnetic liquid. It isn’t a pure substance but rather a compound or solution (ferrate?). All I know is it’s black and can be used to make a nice moving exhibit in a science museum. Oil with iron particles, pretty cool stuff if you ask me. 😃 ---
**Author:** ![Trigonal\_Planar](https://avatars.discourse-cdn.com/v4/letter/t/0ea827/32.png) [@Trigonal\_Planar](https://boards.straightdope.com/u/Trigonal_Planar)\ **Post date:** [February 24, 2004, 2:52am UTC](https://boards.straightdope.com/t/does-liquid-metal-attract-to-a-magnet/230775/8 "2004-02-24T02:52:21Z")
cityboy916 and Ale touched on it. There are magnetic _solutions_ that are being tested in some pretty interesting engineering designs. I know of one particular application by a major car company looking into using magnetic solutions as a break fluid. Using a magnetic field controlled by electric current, the solution can take on any level of viscosity from liquid to solid. The idea is that mechanical break pads can be replaced by this liquid. When you want to slow down/break, the appropriate electric field is generated and the solution quickly solidifies stopping the wheels. When you release, the electricity is stopped and the solution becomes liquid again. ---
**Author:** ![Trigonal\_Planar](https://avatars.discourse-cdn.com/v4/letter/t/0ea827/32.png) [@Trigonal\_Planar](https://boards.straightdope.com/u/Trigonal_Planar)\ **Post date:** [February 24, 2004, 2:55am UTC](https://boards.straightdope.com/t/does-liquid-metal-attract-to-a-magnet/230775/9 "2004-02-24T02:55:56Z")
That should be _brake_, of course! :smack: ---
**Author:** ![Ale](https://avatars.discourse-cdn.com/v4/letter/a/f19dbf/32.png) [@Ale](https://boards.straightdope.com/u/Ale)\ **Post date:** [February 24, 2004, 3:34am UTC](https://boards.straightdope.com/t/does-liquid-metal-attract-to-a-magnet/230775/10 "2004-02-24T03:34:02Z")
Yeah, you usually slow down so you don´t _break_😉 ---
**Author:** ![jovan](https://avatars.discourse-cdn.com/v4/letter/j/0ea827/32.png) [@jovan](https://boards.straightdope.com/u/jovan)\ **Post date:** [February 24, 2004, 4:29am UTC](https://boards.straightdope.com/t/does-liquid-metal-attract-to-a-magnet/230775/11 "2004-02-24T04:29:52Z")
> [@Trigonal Planar](#): > > cityboy916 and Ale touched on it. There are magnetic _solutions_ that are being tested in some pretty interesting engineering designs. [Here’s an art installation](http://oz.hc.uec.ac.jp/~kodama/proflo.html) that uses this kind of fluid. Note that the picture on top is _not_ CG, that’s what the thing actually looks like. And it moves, too. I can vouch for the fact that this thing is very, very cool. There’s a very small video of it in action [here](http://www.siggraph.org/artdesign/gallery/S01/40.html). ---
**Author:** ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)\ **Post date:** [February 24, 2004, 4:38am UTC](https://boards.straightdope.com/t/does-liquid-metal-attract-to-a-magnet/230775/12 "2004-02-24T04:38:12Z")
> [@Trigonal Planar](#): > > cityboy916 and Ale touched on it. There are magnetic _solutions_ that are being tested in some pretty interesting engineering designs. I know of one particular application by a major car company looking into using magnetic solutions as a break fluid. Using a magnetic field controlled by electric current, the solution can take on any level of viscosity from liquid to solid. The idea is that mechanical break pads can be replaced by this liquid. When you want to slow down/break, the appropriate electric field is generated and the solution quickly solidifies stopping the wheels. When you release, the electricity is stopped and the solution becomes liquid again. I believe the term is a magneto-rheological fluid. Magneto- and Electro-rheology are technologies being studied for automotive brakes, clutches, and active suspension shock absorbers. BTW, liquid Oxygen is also magnetic. ---
**Author:** ![scm1001](https://avatars.discourse-cdn.com/v4/letter/s/c4cdca/32.png) [@scm1001](https://boards.straightdope.com/u/scm1001)\ **Post date:** [February 24, 2004, 11:50am UTC](https://boards.straightdope.com/t/does-liquid-metal-attract-to-a-magnet/230775/13 "2004-02-24T11:50:09Z")
> [@Enola Straight](#): > > BTW, liquid Oxygen is also magnetic. actually liquid oxygen is paramagnetic. E.g it is attracted to a magnetic field, but does not in itself have a permanent magnetic field [http://www.physlink.com/Education/AskExperts/ae493.cfm](http://www.physlink.com/Education/AskExperts/ae493.cfm)