Can a supermagnet dangerously affect the iron in blood?

I wouldn’t think the spin axes would align in a liquid. Just because it’s iron doesn’t mean it’s metallic iron.

I met people with similar superpowers. Keeping clean, dust free shoes and an impeccable fold in their trousers while working in the West African bush. Never seen anything like it.

Didn’t know they probably kill me with their looks, too!

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Of course now I want to do a similar test with a torsion balance in a vacuum chamber, controls of empty container, water and other liquids of same volume, vary EM strength and volume and shape of container, but I gave up the Life of Science to do software in the bowels of corporate IT, so someone get on that, will ya.

Didn’t Mystique give the guy an iron filing enema to enable this?


Yeah they pretty much stated that he had to have more than the normal amount of iron in his blood for Magneto to pull that trick, otherwise they’d have to explain why Magneto didn’t just do that to the first guard who walked in the door.


There was also something like that in an episode of the ol’ Lois and Clark: The New Adventures of Superman. (I almost said “a particularly odd episode”, but there were a lot of odd episodes in that series.)

I don’t suppose anyone’s checked out that sponsor? Sounds like a neat idea, but there are so many free educational resources out there already.

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Well how else would the Nevians’ allotropic-iron-extraction beam work?

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Now I don’t have to be super geeky and say this.

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The guy asks whether his super magnet is bad for blood and holds it in his hands in the video. Seems legit.

I don’t know the answer to your question; but at around 16 teslas you can go whole frog; and a levitating frog is just too good to resist.

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Here’s a watermelon taking one for science; and that’s only a 1.5 Tesla field (albeit, as with any medical MRI, a rather large one, not the ‘nominal field strength quoted for surface of magnet’ stuff). Apparently this is why you can get aluminum oxygen cylinders…


The diamagnetism of water is due to the electrons in water, not the hydrogen atom nuclei, but yes, that’s the big failing of this video. Blood is mostly water, red blood cells are mostly water. The magnetic effect the video author observed is due to water, not due to iron in hemoglobin, oxygenated or otherwise.

Things the video gets correct:

  • Physical and chemical properties of substances depend on their molecular structure, not their elemental makeup. Chlorine as dichlorine molecules is a pale green toxic gas; chlorine as chloride ions is table salt. Iron as pure metallic iron is strongly magnetic; iron as rust or iron in hemoglobin is not.

  • Magnetism is due to electrons in molecules, and whether those electrons are paired or unpaired (because the electrons themselves are tiny magnets).

  • The number of iron atoms in blood is negligible.

  • Iron in hemoglobin exists in two possible forms with different magnetic properties.

  • Control experiments are a good idea.

Things the video gets wrong.

  • The appropriate control experiment to assess the hypothesis “does this supermagnet exert a force on a cup of blood?” is not to see if the supermagnet exerts a force on a cup of air. The correct control experiment is to see if it exerts a force on a cup of water. Had he done so, he would have seen exactly the same effect, demonstrating that the iron is irrelevent. The supermagnet is not pushing the blood because of the iron atoms. It’s pushing the blood because it’s water. More generally, it’s pushing the blood because blood is matter, and matter has electrons, and anything with electrons would be pushed by that magnet because anything with electrons is diamagnetic.

  • There are more kinds of magnetism that those seen in deoxyHb (paramagnetism) and oxyHb (diamagnetism). Metallic iron exhibits ferromagnetism, where the magnetic moments of the individual unpaired electrons interact with and affect each other, creating a net moment much larger than would result if the unpaired electrons were randomly aligned. Very strong. You need this for a proper magnet, to generate a significant magnetic field. Matter with unpaired electrons that do not interact is paramagnetic; much weaker that ferromagnetic, but such substances will be strongly attracted by a magnetic field. Matter with paired electrons is diamagnetic; orders of magnitude weaker than paramagnetic, diamagnetic substances are very weakly repelled by a magnetic field. This behaviour is exhibited by frogs, watermelons, pencils, blood, water, and everything else made of atoms, i.e. everything that is matter.

  • The two possible forms of hemoglobin iron are not relevant to the discussion when all the blood is oxygenated. As soon as blood hits sky, it’s oxygenated, and it’s all diamagnetic.

  • The magnetic behaviour of the blood does not have anything whatsoever to do with the iron in the blood, oxygenated or otherwise. Typical Hb concentration is 150 mg/mL. That works out to 0.52 mg/mL of Fe, or 9.2 μmol / mL of Fe. Of the electrons that contribute to the diamagnetism in blood, 0.22 μmol / mL come from iron. That is less that 1/350th the number of electrons in the hemoglobin itself. In contrast, in one mL of water there are over 56 mmol of water molecules, and over 556 mmol of electrons that contribute to the diamagnetism.

The magnetic effect observed in the video is due to diamagnetic repulsion of the paired electrons found in all substances in the blood. For every electron in iron atoms in blood, there are two and a half million electrons in the water. The observed effect is due to water, not to iron.


But then, that reasoning suggests that the empty plastic cup and styrofoam block would also be pushed by the magnet.

I definitely agree that a control with water would be in order here.

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On first seeing the title, I thought this was going to be a thread about MRI mishaps.

I have a spectacularly gruesome story involving a careless janitor and a metal mop bucket…


Oooo! Do share!

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Not much to it, really.

Patient in the scanner, warning signs up telling people not to enter. Janitor ignores signs, opens door and pushes his bucket into the room. Magnetic field grabs bucket, sucks it into the scanner at extreme speed.

The patient did not survive; cleaning out the scanner required a hose.

They revised procedures and added some more locks to the doors afterwards.


Please, please tell me this is apocryphal.


It’s entirely possible. Assuming a steel mop bucket and even a relatively weak 3 tesla magnet, the bucket getting rammed back and forward through the machine’s torus could easily simulate blender action. At a human scale.

Luckily, nobody was hurt in this accident

But you can definitely see how a crashcart could be tuned into a spear shaft. Or possibly the world’s least practical corset.


None of this is helping to assuage my anxieties of ever having to get an MRI in the future:

Technician: [filling out form, looks up from clipboard] And your occupation?
Me: Sheet metal fabrication.
Technician: [rubs forehead, looks back down at clipboard] Oh, fuck.