17 cool magnet tricks

Here are seventeen of our favorite magnet tricks, projects and demos.

Magnet tricks

Extract batteries from stubborn holders
We’ve all got things that take batteries. Some of them are well designed, and some of them are not. The worst offenders are electronic toys that take (say) half a dozen AA batteries, all of which must be inserted with the correct orientation– spring side first– and pried out, well, somehow. Rather than risk puncturing your batteries by prying them out with something pointy, just use a magnet to lift them out.

Magnet tricks
Find studs in your walls

Move a magnet over the wall until it finds a screw or nail head under the paint. You don’t even need to mark the wall– you can just leave the magnet there until you’ve drilled your holes.

 

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Make a homopolar motor

One of our favorite demos of all time is a homopolar motor. A magnet, a wire, a battery and a screw are all you need to make a motor spin up to 10,000 rpm.

 

Make LED Throwies
LED throwies are useful for many more things than graffiti. We’ve made variations from garden lights to origami to greeting cards, but it’s not a real throwie without a magnet.

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Demonstrate magnetohydrodynamic propulsion

You can make your very own caterpillar drive like the one in The Hunt for Red October with this magnetohydrodynamic demonstration.

 

Play with the coolest toy ever: 512 1/8″ cube magnets
Available from K&J Magnetics, this is enough magnets to really have some fun. More magnet sources are in our links section.

Magnet tricksMakeĀ a simple compass

We’ve previously shown how to make stupidly simple compasses that float on water or spin on a smooth surface. Here’s another method: sandwich a thread between two very strong magnets and hang it down for an instant compass.

 

Experiment with self assembly
In a process that is a lot like assembly of biological molecules or crystal formation, randomly ordered magnets can almost automagically form themselves into neat chains. Here are some magnetic self assembly videos.

Magnet tricks

Make almost anything (ferromagnetic) into a building set

With magnets as connectors, you can build tins into anything you like. (Just be sure to get Bawls Mints, not Bawls Buzz).

 

Make a Curie motor
A Curie motor uses heat to demagnetize an area of a magnet, causing it to move away from the heat where the cycle starts again. On BoingBoingTV, Mark Frauenfelder shows you how to build one with a candle, a wire and a couple of magnets.

Magnet tricks
Freaking awesome chip clips

Fold over the open top of the bag and put magnets on either side to hold it closed.

 

 

Play with eddy current damping
Drop a magnet down an aluminum or copper tube, and you’ll see a hovering slow fall caused by eddy current damping. Here’s a quick video.

Magnet TricksMake a fridge pen

Slip a small magnet underneath the metal clip on a pen (these uniballs are our favorite) and you can keep a pen handy on the fridge for your shopping list and phone messages.

 

Defeat magnetic safety interlocks
All kinds of cool industrial machines from photocopiers to deep fat fryers have magnetic safety interlocks to prevent the machine from working with the cover open. Whenever you see a magnet attached to a hinge, it’s there to protect you. So if you ever want to do something ridiculously dangerous like laser engrave your fingernails, you’ll need magnets to disable the magnetic interlocks.

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Make anything into a fridge magnet
We like to make unusual things into fridge magnets. And this trick has occasionally fooled folks into trying to open our fridge magnets to look for candy.

 

 

Demonstrate diamagnetic levitation
By placing diamagnetic material (such as bismuth or graphite) between a large magnet and a small one, you can levitate the small one. Detailed instructions and links to kits for this are on Bill Beaty’s site, amasci.com.

Magnet Tricks
Wake up your laptop or put it to sleep
Many laptops have a magnetic switch that tells the computer to go to sleep when the lid closes. Older Macs could be fooled into going to sleep with their lids up by waving a magnet by the upper right hand corner of the lid. Newer Macs can be fooled by resting a magnet on the switch on the right hand side of the keyboard. Caution: don’t put a magnet near your hard drive!

 

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73 thoughts on “17 cool magnet tricks

  1. Fantastic magnetpost – that one, and the link back to your making your own magnets post. I’ve been making magnets out of other tchotke stuff for years – usually when visitor shops are shortsighted and don’t produce magnets for me to buy. But, I’ve never done it with cool food packaging. Thanks for the idea! I’ll be sure to make one and post it on joy magnetism.

    N.B., I’m a little afraid to put any magnets near my Mac, though… :-)

  2. umm…putting a magnet anywhere near a computer is something I don’t feel comfortable doing.

    Just saying.

    • In order to harm a computer with a magnet, you would need one powerful enough to pull the iron out of your skin. Magnets around computers is okay :P

      • just not around monitors…. to disrupt the hard drive you WOULD need a really powerful magnet

      • Technically that would be /push/ iron out of your skin. Hemoglobin is diamagnetic. : )

        That’s a bit of an exaggeration. But yes, credit cards and hard drives are hard to erase if you are taking basic precautions.

    • putting a magnet, especially a powerful one, near a Mac I don’t have any problem with…

  3. Very cool ideas, i have tons of magents, thanks for giving me something to do with them all = )

    Oh and btw, i have worked in IT for 6 years now, and I’ve always been told that you don’t want to put a magnet near a hard drive. 3 months ago in my lab here at work, i was physically destorying IDE hard drives, i would open them up and scratch or bend the platers. Anyway…I took a large magnet (actually from another hard drive) and i put it on the plater and spun it around a few times. Then i plugged the hard drive back in and it worked just fine. Nothing will actually happen to a hard drive if you put a magnet near it…if you’ve opened a hard drive before there is a VERY powerful magent in the hard drive… I will repeat… VERY!! powerful magnet in the HDD. watch your fingers – that’s all i’m going to say.

    • just don’t use rare earth magnets around your computer/laptop. that’s how to destroy a drive. regular magnets don’t do much to computers at all.

      • Magnets are magnets, the magnetic force is the only thing different between the different materials.
        You do know that hard disks have strong magnets in them don’t you?

        • True, hard drives contain very strong magnets. The magnets are however arranged in such a way that the magnetic field is only strong in the gap between the two magnets. Hold an iron nail outside of this assembly and observe the weakness of the field, then hold the same nail near an exposed magnet and compare. The metal frame that the magnets are mounted in is responsible for acting as a conduit that connects the north pole of one magnet to the south pole of the other. The magnetic field likes to follow this conduit and thus very little field escapes. This connection should also serve to increase the strength of the field in the gap between the two magnets.

          • all hard disk drives manufactured in the last ten years are encased in "mu metal", which acts as a shield for low frequency magnets such as rare earth, ferrite, etc..

            mu metal is the only known material able to deflect the magnetic fields of ‘permanent’ magnets. magnetic ‘flux’ (field) will pass through even lead, but not thru hard drive casings.

            thus, you could wave a huge foot-long rare-earth magnet over your hard drive with no detrimental effect.

            • I’ve personally seen magnets destroy hard drives. At my old job, engineers placed antennas with magnetic bases onto tractors to carry out tests. Many times, they would forget and place the antenna on top of the laptop when they were finished and we would have to rebuild the PC with a new drive.

              • Are you claiming you had to rebuild the PCs with new hard drives, or rebuild the PCs with other components, because I’m gonna have to raise the BS flag on this one. (Unless, as previous comments have mentioned, your HDDs were not encased in mu metal).

                To be honest, i think you’re full of crap (as i think when any personal anecdote contradicts science), but If your computers did in fact get damaged then it was most likely that the magnets screwed with the data on rom chips on the motherboard.

                My guess is that you were not involved with fixing these computers and you just assumed the cause and solution.

            • you have to put a magnet of equal or more power than the magnet in the HD, on the other side of the drive (or across the physical disk and pin) from the original magnet. The magnetic force pulling across the disk will destroy it, and lift the pin off the disk to prevent any form of read/write capability

    • Nope, all spinning hard drives have several magnets, typically including two that are extremely strong rare-earth varieties. They are fixed solidly to the hard disk frame leaving a narrow slot. The read/write head arm pivots, with the heads on one end and a coil of copper wire (snugly fit between the magnets) on the other. Apply voltage to the coil, and voila! Deflection! They work in exactly the same way as permanent-magnet speakers; the term "voice-coil actuator" was once common in hard drive specs, but they’re all voice-coil these days, so you don’t hear much about it…

    • You’ve never disassembled a dead hard drive, I see.
      (The magnets inside hard drives are pretty strong.)

  4. make sure you don’t use any rare earth magnets around small children, there has been an increase in stomach and intestine puncturing from ingesting two or more of these strong magnets

    • The tissue doesn’t need to be punctured or torn to cause potentially serious problems; just having it pinched together is enough.

  5. I use the little ones ($.05/ea try google). to hang my pens from my cabinet and to post notes on my (steel) door frame in my office.

    • i have about 200 magnets from microwave ovens (magnetron tube) as they are circular in nature i have made not much use for them except for putting them on a fridge and using them to put slips of paper on them as well as puting small metalic objects like scews on them while working on projects so they will not get lost.. any other uses for them?some are so strong that you can thow them in the air & will clack together.. impressive if your finger is not there

      • I stuck a big circular microwave magnetron magnet under the kitchen cabinet by our kettle. I hang teaspoons and other ‘in use’ cutlery from it to save leaving muck and drips on the work-top.

        It’s only held on by a big blob of blue-tack but it hasn’t ever come down. It’s invaluable. :D

    • "I use the little ones ($.05/ea try google). to hang my pens from my cabinet and to post notes on my (steel) door frame in my office."

      Is that a typo? "Pens"? Or…

  6. I use magnets as tie tacks. It doesn’t put a hole in your tie and you can always find some sort of strange button magnet that gets some strange looks.

  7. Trust me, I tried it once (ages ago) on a PowerBook using a strong magnet – ended up with a bad track on the disk (and a lot of clunking forever because the heads kept trying to align or something…)

    A safe magnet to use for sleeping your mac laptop is a fridge magnet. I used (after the above incident) a fridge word (you know, like you get to make sentences on your fridge).

    If you get the position just right it sleeps fine, and way too weak to even think about worrying your disk.

  8. I’ve got a question !!!!!
    Does anyone know what happens when a magnet is near an LP or LP player?

    does it get destroyed??

    • No… The tracks on a LP Record are actual, physical material variations… think like, swooping through the Grand Canyon… The "Needle" (most modern needles are actually thin, flat strips of metal) simply skips along those bumpy canyons. If you listen to a record playing with no speaker, you will notice you can hear the song’s beat and even some vocals, this is because a record is what you call Analog… meaning the sounds are merely amplified readings of physical waves (the bumps in the record’s canyons or grooves), This is also why they still exist… Audiophiles tend to prefer LP records as the sound they reproduce is based on the precise waves produced by the instruments and vocals themselves… just shrunk…

      No magnet can destroy the reproduction capacity of any record… only time and heat.

    • Yes, if you bring an LP near a magnet, the magnet will be destroyed. See, a record works because the needle of the record player vibrates in the grooves; those same vibrations would shatter any type of magnet you put near it.

    • QUESTION OF THE DAY—-

      How many grooves are there on each side of an LP record? Lets assume it’s a 20 minute record that plays at 33 1/3 RPM. That should make it easy.

      Wardriver

      • It depends on the LP. Obviously one is the normal answer, but for example this reference from Wikipedia shows the answer could be as many as 8:

        http://en.wikipedia.org/wiki/Unusual_types_of_gramophone_records#Parallel_grooves

        In 1975 Ronco UK released a parallel groove game called "They’re Off", which featured three 12" discs each containing eight possible outcomes on a horse race. It featured Noel Whitcomb, a well-known horse-racing commentator of the day and the game revolved around betting which "horse" would win the race on that occasion. This appears to have been based on a Canadian product called "They’re at the Post" by Maas Marketing, which is more or less the same game with different recordings on the discs to reflect the target market.

  9. if a baby ingest two of these at different but close enough time intervals, it will be a huge huge disaster….

  10. Here’s my tip: if you stick a small rare-earth magnet to the top of your can-opener, you can use it to lift the lid out of the can without risking cutting your fingers or getting covered in juice.

    If the magnet’s strong enough, it will stay in place despite passing through a dishwasher etc.

  11. I’ve heard you can use magnets for running wire down walls. Basically take some metal chain and tie it to the end of your wire and use a powerful magnet against the outside of the wall to pull it down to exactly where you want to go.

    I plan on trying this out for running some ethernet cable from one room and over the attic and down into my living room. Enjoy!

    • I actually did this a few years ago when I had to run some ethernet cable from the upstairs to my downstairs office. It works like a charm.

    • i buy my unlnessisarily strong magnets at magnets4less.com, or magnet4less, i forget. anyways theres a couple good websites around. k&jmagnetics is also good. If you live In the states check out UnitedNuclear

  12. Uh, if you want to put your Mac to sleep, why don’t you just click on Sleep in the Apple menu? Especially since on the MacBook at least the bottom right corner is exactly where the hard drive is…

    • I’ve got a cool magnet trick. Try attaching a strong, small magnet to each finger tip (glue or tape) and feel the magnetic pull of objects around the house :)

    • Haha, that’s pretty funny. I like this article, although the laptop idea doesn’t sound like something I would try.

  13. hahaha yeah i blew an ibook when i was playing with a magnet and it fell right over the hard drive

  14. Just discovered that my quarter inch cube magnets make great clothespins when coupled with the wire rack in the laundry room.

  15. I have an interesting magnet trick for the holidays…
    Have you ever dealt with a fake steel Christmas tree? After about 2 years of use, some rings begin to slip (among other things…) so, what I found, is that you can support those rings by… placing a magnet under them!
    … and I guess, in theory, you could make a magnetic Christmas ornament too!

  16. Yes, that’s the real question. Or better yet, how do you protect a metrocard from being becoming unreadable after coming in contact with a magnet on a wallet or bag?

  17. Incredibly strong!! I had to use two pairs of channel lock pliars to separate two magnets that I got
    out of old hard drives.

  18. The hemoglobin molecule is diagmagnetic, yes, but the magnetic moment is so small that there would be no notable effect–or so I suspect. Also, the iron in hemoglobin is NOT ferromagnetic at all. Major misconception on most people’s part–it helps sell a lot of useless "miracle" cures using magnets.

  19. here’s a cool magnet trick. if you’re like me and you have a problematic door that won’t close because it is smaller than the frame, install four magnets inside the frame; a pair near the top & a pair near the bottom. presto, close-o!


    i taped a phone to my balls and they call me nuts.

  20. A really heavy strong magnet superglued to your forehead will make you smarter. It won’t improve intelligence by much, but it will improve your wisdom eventually. For instance, you’ll learn not to trust random advice from perfect strangers. ;P

  21. mean either it would ruin them ……i tried it on my computer and guess what …………………it never turned on again

  22. I bought a magnetic ring and so far it has been fun. Whenever I use the microwave, blender, or similar things the rings vibrates on the finger. It is really cool but I do not know if it is dangerous. So far my finger is fine. It makes it easy to hold some forks, spoons, and knives. I found out by mistake about the finding studs trick when I placed my arm on a wall one. I was like wth, my finger is stuck to the wall.

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