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April 4, 2014 4:11 PM   Subscribe


 
Hey, I've built one of these. They're pretty cool. Well, they get really hot actually. Science!
posted by spikeleemajortomdickandharryconnickjrmints at 4:16 PM on April 4 [1 favorite]


Can this get coupled to a rail gun?
posted by GuyZero at 4:58 PM on April 4 [1 favorite]


This must mean that desktop fusion is only a couple of months away!
posted by sneebler at 5:01 PM on April 4 [1 favorite]


It's neat that it continued to levitate after it was completely liquified.
posted by Chocolate Pickle at 5:06 PM on April 4


Neat!
posted by carter at 5:20 PM on April 4


This may be the most (only?) intelligent set of YouTube video comments I've ever seen:


Great video but I think that the title is wrong. Aluminium isn't magnetic so it wouldn't levitate... Steel perhaps?

Reply

It is indeed aluminium, it melts before it glows. The cylinder floats because of electromagnetism, caused by Foucault current in it, not permanent magnetism.

Reply

I thought the same thing as Mark, but thank you for your post IOOI after a quick Google of Foucault realizing it is an Eddy current I then understood what you were talking about. If I am understanding it correctly the current in the electromagnet is actually generating a current in the chunk of aluminum and like a stater in an alternator creates its own free floating electromagnetic field which holds it suspended until they turn off the main electromagnet. At least that is what I think is going on.
posted by Muddler at 5:24 PM on April 4 [8 favorites]


The pink glow and the rapid cooldown at the end remind me of early sci-fi special effects.
posted by ceribus peribus at 5:32 PM on April 4 [1 favorite]


Interesting the way the copper coil doubles back on itself at the top for most of a turn-- is that to generate an opposing field at the top and keep the cylinder in there?
posted by jamjam at 5:36 PM on April 4


Just imagine if the alchemists had these coils. I bet they would have won.
posted by thelonius at 5:48 PM on April 4 [1 favorite]


So, they're pumping both water and electricity through that copper tubing? Pretty badass.
posted by valkane at 5:49 PM on April 4


I used to work in an aluminum foundry. Molten aluminum looks cool and can be fun to play with. (Yes, that is exactly as unsafe as it sounds.)
posted by double block and bleed at 5:59 PM on April 4 [1 favorite]


Knife makers have been experimenting with these recently as well.
posted by the_artificer at 6:00 PM on April 4


It is indeed aluminium, it melts before it glows.

This, by the way, is reason #2 why welding aluminum is hard. Reason #1 is the thermal conductivity.
posted by eriko at 6:02 PM on April 4 [3 favorites]


I think this could potentially be very interesting if applied to space-based manufacturing.
posted by heathkit at 6:18 PM on April 4


Knife makers have been experimenting with these recently as well.

Ah, OCP. Makes sense, since they produced both the ED 209 and that other guy.
posted by valkane at 6:37 PM on April 4


That's really cool.

I love that you can really see how inexorable gravity is; as the aluminum melts it still starts flowing down. I wonder if the magnetic field was stronger if the aluminum would be more spheroid like liquid in microgravity or did I just bang into the limit of my understanding of physics?

I also love how s/he's just poking it with a pencil. I mean I'm sure it's a science* pencil and all...

This may be the most (only?) intelligent set of YouTube video comments I've ever seen...

I have to think that all the comments (that I read) on this video must violate the youtube TOS for being: Reasonable, literate and not insanely bigoted. actually sometimes youtube comments are on point these days or at least funny and positive, but still it's an outlier.

*On reflection I realize it's probably an engineering pencil, but the lines are blurry.
posted by Divine_Wino at 7:10 PM on April 4


Interesting the way the copper coil doubles back on itself at the top for most of a turn-- is that to generate an opposing field at the top and keep the cylinder in there?

Pretty much exactly that.

If you create such an apparatus without that, you have a railgun.
posted by Pogo_Fuzzybutt at 8:17 PM on April 4


The lines might be blurry, but not as much as if they were made by a social science pencil. I'll see myself out.
posted by JHarris at 8:18 PM on April 4 [1 favorite]


Science pencil.

Personally, I'm a huge fan of Science tape and miss it so terribly. Also Kimwipes. Man, I miss Kimwipes.
posted by porpoise at 8:20 PM on April 4 [5 favorites]


There need to be more Science ThingsTM.
posted by JHarris at 8:57 PM on April 4


Personally, I'm a huge fan of Science tape and miss it so terribly.

I've been trying for years to explain how awesome this stuff is.
posted by underflow at 9:10 PM on April 4 [1 favorite]


Very cool! Why boss808 didn't set that video to dubstep, though, I don't know.

Bunch of questions for anybody who knows anything about science:
Once the aluminum cools and hardens again, will it just be one mass or will it stick to the ground? (For the sake of boss808's security deposit, I'm hoping the former!) How long will it probably take to cool? How hot do you think it was at that point? Would it be at the same temperature as its melting point, because any aluminum at a higher temp would start evaporating? Wait, is there evaporated aluminum all around the induction heater after melting the slug?!

Anyway, I'm tempted to try that DIY induction heater because it sounds fun, and because I would feel like such a badass using it to boil the water for my morning coffee.
posted by rue72 at 10:31 PM on April 4


Needs a cup of lox under the coil.
posted by ryanrs at 11:03 PM on April 4


Once the aluminum cools and hardens again, will it just be one mass or will it stick to the ground?

I don't have an induction heater, but I did build an aluminum smelter. Molten aluminum is super awesome (as double block and bleed mentioned). It's glossy, shiny, thinner than water, and somewhat north of 650 C. You need to be really careful when moving a crucible full (or even kind full) of molten aluminum as it's easy to slosh around.

If you do manage to spill some on a concrete patio it will cling to the surface but can be fairly easily pulled up once it cools. I don't know how long it will stay too hot to touch when splattered on the ground as I poured water on the spill after a few minutes. The dross I skimmed stayed super toasty for quite a while when dropped into a bucket of sand.

I would feel like such a badass using it to boil the water for my morning coffee.

This is exactly how science and engineering technology advances.
posted by flyingfox at 11:46 PM on April 4 [2 favorites]


Note that you will need to put a chunk of aluminum in your coffee.
posted by ryanrs at 11:57 PM on April 4


The reason for the pencil is probably because any probing tool would have to a) not conduct electricity and b) have a high melting point. Graphite has both properties and would have been handy.

That aluminium was hot. The notes on the video say 1200 degrees C. Judging from the chart here, that seems reasonable. That's hot, but aluminium melts at about 2700 degrees C in standard conditions. Not a physicist, but while a few more excited atoms may have escaped the mass, I doubt that there were many at all. The situation is complicated by the magnetic current - I think any stray atoms will be contained by the fields and pushed back into the centre. A proper physicist would be to answer that one far better than I.

Fluids do not need to be at the melting point to evaporate. The closer they are to their boiling point, the faster the evaporation. Evaporation does cool the fluid, but the rate of heat loss would be minimal in comparison to the heat being generated by the inductive coil, so the aluminium would have quickly gotten past its melting point.

The aluminium block wouldn't take long to cool once it fell - the block is small, aluminium has excellent heat conductivity and the pancake has a very large relative surface area. It seems to take about two seconds for it to go from 1200 to 600 odd degrees, so give it a minute and it should just be warm to the touch.

Boiling water with an induction coil could be interesting if not carefully controlled. See here.
posted by YAMWAK at 1:42 AM on April 5 [2 favorites]


Oops - think I was wrong about the pencil - induction forges can light up graphite. Forgot about that.
posted by YAMWAK at 1:47 AM on April 5


I feel like there's an element of human nature in a nutshell about this: "There's a glowing, levitating ball of molten metal in front of me. ......... I should poke it."
posted by Wolfdog at 5:19 AM on April 5 [9 favorites]


I like that you can see some aluminum cow patties in the background from the very beginning of the video. Foreshadowing!
posted by moonmilk at 6:04 AM on April 5 [1 favorite]


"Just imagine if the alchemists had these coils. I bet they would have won."
I'm guessing that if the alchemists had coils like those we'd be using gold foil to wrap fast food and probably have those damn flying cars!
posted by TDavis at 7:31 AM on April 5


Could we add a switch that turns it into a magnetic gun that shoots the slug of molten metal?
posted by pracowity at 9:43 AM on April 5


This is exactly how science and engineering technology advances.

The energy efficiency of the cuppa can be improved by filling the cup with water pre-heated by passing through the coil's cooling channel.
posted by anonymisc at 11:20 AM on April 5


That's neat, but how do I weaponize it?
posted by MeanwhileBackAtTheRanch at 11:41 AM on April 5 [1 favorite]


That's neat, but how do I weaponize it?

I don't think it's likely ever to be remembered in the same breath as his anticipation of the geostationary satellite, but a crucial turn in the plot of Clarke's A Fall of Moondust centers around such a device.
posted by jamjam at 12:17 PM on April 5


What did that guy Clarke say about magic? Yeah. This kinda looks like it.
posted by valkane at 3:35 PM on April 5




That's neat, but how do I weaponize it?

You saw that GI Joe movie, right? You just put it in a Weaponizing Machine. It'll hover, glow a bit, and spin around real fast for a little while. There you go, all weaponized.
posted by JHarris at 8:16 PM on April 12


If you create such an apparatus without that, you have a railgun.

Wouldn't the lack of a physical connection to pass the current through the object make it a Gauss gun?
posted by ROU_Xenophobe at 8:33 PM on April 12


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