magnetism and you. also, small particles

[MrDudeMan]

how does magnetism go through your body and not hurt you? for example...if you take 2 powerful magnets, put one on each side of your hand, they pull together through your flesh but it doesnt hurt you. that is just amazing to me.

something else id like to ask/talk about...what could be smaller than the smallest particles known today? how far do you think it can go? i know basics on this stuff, but i am curious what other people know regarding new, small particles being researched currently.

gravitons would be a neat find if they actually prove their existence.

 

[JAGedlion]

I'm sure strong enough magnetic fields would definetly hurt you, but in it seems to me that generaly the amount of force the field acts up the small charged particles in your body (most are uncharged, probably even non polar, yea, I'm not including water in that ) is just too small to significantly affect their ability to do whatever it is we want them to.

 

[MrDudeMan]

Originally posted by: JAGedlion
I'm sure strong enough magnetic fields would definetly hurt you, but in it seems to me that generaly the amount of force the field acts up the small charged particles in your body (most are uncharged, probably even non polar, yea, I'm not including water in that ) is just too small to significantly affect their ability to do whatever it is we want them to.

every particle has charge, though. its weird that it doesnt really mess stuff up, even if the cells have such a small amount of charge.


maybe charge isnt the right word, but i know all particles can be attracted to a magnetic field. what was that huge electromagnet project called? you know, the thing that suspended spiders and frogs without hurting them?

 

[everman]

Living things like insects, and I do recall seeing a frog too, have been suspended in magnetic fields with no ill effects.
I'm sure if you could get two very strong fields pulling on an object it could be damaged.

 

[jagec]

Originally posted by: JAGedlion
I'm sure strong enough magnetic fields would definetly hurt you, but in it seems to me that generaly the amount of force the field acts up the small charged particles in your body (most are uncharged, probably even non polar, yea, I'm not including water in that ) is just too small to significantly affect their ability to do whatever it is we want them to.

It's REALLY high. MRI scanners get up to 30,000 Gauss or so (the earth's field is .3-.6 Gauss). Apparently people working around 40,000 Gauss fields have reported vertigo and nausea, but mostly only when they make rapid head movements in the field.

more info:
http://www.mcw.edu/gcrc/cop/st...ds-cancer-FAQ/toc.html

 

[Calin]

Originally posted by: jagec

Originally posted by: JAGedlion
I'm sure strong enough magnetic fields would definetly hurt you, but in it seems to me that generaly the amount of force the field acts up the small charged particles in your body (most are uncharged, probably even non polar, yea, I'm not including water in that ) is just too small to significantly affect their ability to do whatever it is we want them to.

It's REALLY high. MRI scanners get up to 30,000 Gauss or so (the earth's field is .3-.6 Gauss). Apparently people working around 40,000 Gauss fields have reported vertigo and nausea, but mostly only when they make rapid head movements in the field.

more info:
http://www.mcw.edu/gcrc/cop/st...ds-cancer-FAQ/toc.html

That would be because there are currents in nerves going back and forth, and there are electric charges in cells. The fast head movements will just create currents in the conductive channels of the nerves. It is just like moving an solenoid in a magnetic field - you obtain current.
A magnetic field strong enough would take the iron out of your blood (haemoglobin)
(but this is a joke, the iron atoms into the heamoglobin are "fixed" in place by other atoms, so there won't be a magnetic effect)

 

[Squally Leonharty]

Originally posted by: Calin

A magnetic field strong enough would take the iron out of your blood (haemoglobin)
(but this is a joke, the iron atoms into the heamoglobin are "fixed" in place by other atoms, so there won't be a magnetic effect)

Heh, go watch X-Men 2. You can see that haemoglobin happening between Magneto and a cop. Pretty cool.

 

[DrPizza]

however, you can but your wheaties in a blender, and using a really strong magnet, separate out the fortified iron (or so the little list of experiments to do in class says.... I'm not wasting my time with that one unless someone can verify for me that it's impressive)

Also, in the past, (I'm not sure about currently), there was a belief by orthopedics that the use of magnetic fields aided in the repair of broken bones.

 

[itachi]

blood is only one of the many places where iron can be found in the human anatomy.. actually, there probably isn't a single cell in the body that doesn't contain iron. it's the basis for nmr imaging.

changing magnetic flux induces voltage, not current. also, i dont think that an induced emf would be the primary cause (or even a cause) of the nausea when people move their heads rapidly in a magnetic field. the hall effect seems like it'd be the more likely explanation.. more specifically, the lack of equilibrium that would result from rapid head movement (reached when the electrostatic force balances the magnetic force). different parts of your brain would increase and decrease in charge rapidly.. every part of your brain would be getting signals (kinda like a seizure).

 

[Gibsons]

Iron is an essential component of a few proteins in the respiratory chain in mitochondria, so it should be present in all cells. Iron's thought to be necessary for most forms of life as we know it; iirc lactobacilli are an exception.

I did a volunteer study as an nmr subject once. Only effect I could notice was a slight decrease in air pressure when they turned it on (I was holding my breath and laying still as instructed... could feel the air in my lungs "swell" a slight bit when they turned it on).

 

[Mark R]

Iron in the body is present as Iron (II) chelated in a variety of forms - either in haem (as part of haemoglobin and some cytochome enzymes) or as at the active site of some other enzymes. In this state Fe2+ is not ferromagnetic, so a strong static magnetic field would only produce the tiniest of forces.

The main problem with very strong static magnetic fields is that movement through them will generate electric currents, which may cause a wide range of symptoms. Rapidly changing magnetic fields (as can be found in some state-of-the-art MR scanners) can induce significantly stronger currents, and can cause symptoms like pain or twitching muscles. It's worth remembering that the main magnetic field in a typical MR scanner is always energised*- only the very much weaker localising fields (used to select imaging planes and voxels) are switched on and off.

MR imgaing doesn't image iron - it images hydrogen (usually) and therefore water and fat. There are several techniques which can provide contrast on other features of the tissue being imaged, but the fundamental image is based on hydrogen content. Recent advances have enabled imaging of other atoms - e.g. hyperpolarised helium-3. That's not to say that iron doesn't affect MR images - it can do. Certain diseases e.g. haemochromatosis which causes excess iron to be deposited in organs like liver, can effect the images due to a property called magnetic susceptibility.


* - as the main electromagnet is superconducting (therefore needs no energy to stay energised), there is little point in turning it off. However, as it is very expensive (anything up to $1million) and its structure is partially supported by the several tonnes of magnetic repulsive force on its coils, switching it off and on is generally avoided because there is a risk of buckling the coils.