How are Magnets made?(science)

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My 4 year old daughter came home from a friend with a pair of the most powerful magnets I have ever seen. They are the size of quarters and one can easily move the other through 2 inches of would. She's had a lot of fun with them and asked the inevitable question of where they come from. So I looked in encyclopedias, but really didn't find a sastifactory answer. I figured the collective wisdom of this forum would include a definition that I can understand, and relay to my kid.(ok, she probably would have understood the encyclopedic description, so this is for me) How are they made, who makes them, and why are some better than others? Why don't they make the strips at the craft store good enough to hold up a piece of paper? Does the use of these strong magnets have anything to do with the fact that I can rob a watch battery of all it's power in the length of time it takes me to get home from the store where I bought it? I don't spend much time with the magnets, but thought this phenomena may have begun at about the same time they got here. Thank You, Jill

-- JillSchreiber (schreiber@alaska.com), April 19, 2001

Answers

Jill - don't know a thing about magnets other than that 'pull' is an electrical charge. I know that they pulse electricity into the 'super' magnets... But that's it. Don't know what current is used, and don't know how the charge is kept. Sure would love to have a couple of magnets like those your daughter brought home, though! LOL!!

-- Sue Diederich (willow666@rocketmail.com), April 19, 2001.

Jill:

Magnets can be made with Cobolt, Nickel, and Iron and some cermacis. Magnets are basicaly made by applying a electric field to one of theses elements or their alloys. The electrons of these metals then all line up in the came direction producing magnitic poles. The reason the earth is magnetic is because we have an nickel/iron core which is rotating (hence, North and South pole). Wow, your friends at a dinner party with that one some time. It's a realy show stopper! :O)

Also, If you want to be McGyver you can make a electomagnet by wraping an extension cord around a iron bar. It will stop working when the cord is unplugged.

To answer why some magnets are stronger then others. It comes down to alloy compostion. Nickel and Cobolt are very expensive. So cheap magnets have less of these elements. That way it does not cost 100 bucks to hang you daughters art work on the frig! :O)

Magnets are cool! I've done a lot of work with magnetic alloys for computer hard drive applications, but that's another story. :O)

-- Storybook Farm (Ozarks) (mumaw@socket.com), April 19, 2001.


To further add to the answer, "refrigerator" magnets are made of powdered ferrite mixed with a synthetic resin or rubber to give either individual moldings or extruded strips, or sheets, that are semiflexible and can be cut with knives. This material has been used as a combination gasket (to make airtight) and magnetic closure device. These are some of the weakest magnets.

Next in strength come the plain iron magnets, then steel which makes a better permanent magnet than does soft iron. The other elements mentioned add greatly to the ability to hold a magnetic charge. The composition of magnetic materials is a metallurgical subject in itself and there are people dedicated to this science.

Yes, the earth acts like a giant magnet, however very weak. Actually it is a dynamo (like and electric motor).

In general the smaller and stronger a magnet, the more exotic the materials (and of course, expensive). We use magnets every day in our devices, the most common being audio speakers, phone sets, microphones and computers.

-- Lynn Goltz (lynngoltz@aol.com), April 19, 2001.


I magnetize my own tools when neccessary by using an electromagnetic coil wrapped around the tool, connected in series to a 10 ohm load resistor , then apply dc voltage to the coil from a battery or power supply. This aligns the magnetic lines of force in the steel magnetizing the tool. The effects last a couple of months before needing to be done again.

-- Jay Blair in N. AL (jayblair678@yahoo.com), April 19, 2001.

Magnets are indeed fun to play with. Insulated wire can be wrapped around a small bolt or even a 16# nail to make an electro magnet, and hopefully you will power it with a latern battery, not 110V.

You can also use an automotive testing device known as a growler to magnetize screwdrivers and such.

I seem to remember that you can also tap a bolt many times on it's head and somehow that aligns it's structure to create a weak magnet.

The rare earth magnets are often sold at a reasonable price on EBAY's auction site. There is also a warning there about playing with the very strong magnets, as fingers can get pinched easily by them if you are not careful.

-- Notforprint (Not@thekeyboard.com), April 19, 2001.



Hello Jill, If you take a magnet and rub it against a piece of steel about tweenty or more times, the magnet will magnetize the piece of steel. I do not know if it will be as strong as the original magnet but, I know that it does magnetize. Sincerely, Ernest

-- http://communities.msn.com/livingoffthelandintheozarks (espresso42@hotmail.com), April 19, 2001.

I am not sure if it is the individual atoms or molecules that have the magnetic field but every 'magnetic' type substance (such as iron) has a magnetic field around every one of it's atoms (or molecules, as I say, not sure which).

To magnetize the material all that is required is to shake these around so that the magnetic fields are all working the same direction.

The strong magnetic field from an electric field will do it as will stroking the material with something already magnetized. Even tapping the material will get a bit of magnetism as the tiny fields get lined up with the earth's magnetic field.

Heating a magnet agitates it somewhat and the fields get all jumbled up again, hence not 'a magnet' anymore.

Some magnetic materials are quite soft so that although they can be magnetized most of it is lost once the magnetizing influence is removed. Soft iron in a transformer is magnetized one way then the other 50 or 60 times a second, when you turn the power off most of the magnetism disappears.

-- john hill (john@cnd.co.nz), April 19, 2001.


Just for the plain old golly gee whiz of a factoid, I read in a couple different article that the super high powered electromagnets in those giant super colliders that they smash atoms in will literally rip the iron right out of your red blood cells, destrying them instantly and catastrophically, if you have the bad luck to get caught in with them when they get turned on (assuming, of course, the shielding is somehow down). Ouchie.

-- Soni (thomkilroy@hotmail.com), April 20, 2001.

Hmmmm! I thought the iron in our blood was in the form of iron oxide, which I don't think is magnetic. I could be wrong on all points!

-- john hill (john@cnd.co.nz), April 20, 2001.

Thanks for all the responses. I think I have a better understanding, and knowledge that I don't have to put up with those cheesy magnates any more! After I read some of your responses to my machinist hubby he came up with some interesting stuff too. His metal lathe tools become irritatingly magnetized (think of the metal sawdust sticking to them)and he has a demagnetizer. I asked him to bring home the manual for that so I can see the reverse process. Thanks again for all the responses. Jill

-- JillSchreiber (schreiber@alaska.com), April 21, 2001.


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