Fun with Neodymium Magnets

[Thunderbolt]

Since I detect some passing interest in science around here, I wanted to share my recent eBay indulgence with you.

Nottingham University has done a series of YouTube videos called Periodic Videos, where they talk about the elements in the periodic table. Of course they are not above doing some mad cap experiments, usually of the alkaline metal variety!

One clip that intrigued me was the one on a rare earth called Neodymium, and how it is used in super strong magnets. A few clicks later and I found an eBay shop selling them and since they are cheap, bought two of the strongest ones available, rated at N52 and generating 40KG of force each.

They are only 2.5cm wide by 2cm deep, but even at that size they are incredibly powerful, in fact they come with safety warnings, and I thought they were joking till I took one out of the safety carrier and placed it against the other (still inside its safety carrier), now I know why they tell you to wear gloves.

If you are not squeamish and want to see how terrifying these things REALLY get, check out www.magnetnerd.com. Somebody had a bad accident with a big one of these...

 

[Spinward Scout]

Don't know if this really works or not but here's a video with those types of magnets:

http://www.wonderhowto.com/how-to/v...fic-lights-to-change-from-red-to-green-78256/

 

[far-trader]

Don't know if this really works or not but here's a video with those types of magnets...

Interesting but my BS meter was pegged over almost right away

If these magnets are so powerful why did he need to double sided tape them to his scooter frame? Is it aluminum? Doubtful.

And that little magnet, even if it was Neodymium, wouldn't strike me as powerful enough to affect that large an area. I thought a bigger one maybe but...

...check the feedback, one guy tried it, with 7 times the magnets, and it didn't work.

I'll wait for the Mythbusters episode (have to send that one in if it hasn't already been suggested, they like playing with the Neodymium magnets, just have to figure out how they can get it to explode the traffic light )

 

[ganymede]

Yeah, just invest in a divers' magnet, tie that to your chassis, then you'll never worry again. Of course the fact that it's, like, 20 lb of iron might help as well.... You could tie it off with the nylon cord that usually comes with it and drag it behind you: pick up pennies along the way! After putting a good 20,000 miles of city traffic on that scooter you might have picked up enough conductive change to pay for the magnet!

 

[DaveChase]

I vote for MythBusters. If they prove it, then wow.

If they disprove, just another thing to add to Traveller as neat to know for that Scienist or Engineer type.

Dave Chase

 

[Icosahedron]

I got a few of these some years ago. Just a few millimetres across. They're amazingly powerful for their size and I can imagine large ones being dangerous. My little ones will attract each other from almost a foot away, so I could easily see big ones flying across a metre or more of space, with several Gs of acceleration. A magnet the size of a can of beans would have the same effect as a similar size hammer. You certainly don't want your extremities between them!

I'm not so sure that magnets that small on the scooter would activate the sensors any more than the body of metal - I think they'd need to be bigger. I was puzzled by the double-sided tape, too. Probably valid in theory but BS in practice.

In a similar vein, how about climbing a skyscraper by attraction to the steel frame through the concrete skin?

 

[Zutroi]

The Mythbusters have used these little jewels on a few occasions, including:

James Bond's Magnetic Bullet Deflector...
Climbing thru the air ducts to sneak into a building...

and

Civil War bullets fused in mid-flight!

 

[saundby]

A former employer manufactured hard disk drives. We used to play all sorts of games with the rare earth magnets taken out of production fallout units and other scrappers.

Amazing people with eddy current effects was always fun. We had a jig that we used to make up by welding it together. Someone figured out we could make it with a magnet instead and have it work just as well. I'll never forget someone trying to pick a magnet off one for another use and becoming convinced it was one of the welded jigs after fighting to get the magnet off for half an hour. A closer look later revealed that it was, in fact, a magnet, just one that was a bit more persistent than the others.

 

[coliver988]

At the cycle shop I went to for 19 years (same motorcycle) they were selling magnets you fasten to the bottom of your bike that were suppose to help with the lights (and I've been stuck at lights a long time, eventually running them). Mary, the owner, said she had a bunch of riders test them and that they actually did work. I didn't get one so I've no idea if it did or not, but the owners of that shop were very honest so perhaps they do. I can't recall the price but it was relatively cheap.

 

[ganymede]

Interesting but my BS meter was pegged over almost right away

If these magnets are so powerful why did he need to double sided tape them to his scooter frame? Is it aluminum? Doubtful.

And that little magnet, even if it was Neodymium, wouldn't strike me as powerful enough to affect that large an area. I thought a bigger one maybe but...

...check the feedback, one guy tried it, with 7 times the magnets, and it didn't work.

I'll wait for the Mythbusters episode (have to send that one in if it hasn't already been suggested, they like playing with the Neodymium magnets, just have to figure out how they can get it to explode the traffic light )

The scooter is probably plastic; most scooters are below the lower limits for motor vehicle regs. But a weed-wacker motor's not gonna push anything unless it's light, and though there are metal components, most of those scooters out there are plastic or aluminum. At the prices I've seen them at, probably aluminum.

 

[Captain_Ahab]

I don't know about magnets, but I DO know about traffic signals and how they work ( I repair them for the NJ Dept of Trans. ).

Those induction loops have adjustments for sensitivity and if you need a magnet to be detected, they're probably adjusted wrong. I've seen some that were sensitive enough to detect bicycles.
The video seems to imply that putting these magnets on will cause the light to change immediately...wrong in most cases. The loop simply tells the signal controller that there is traffic there waiting, AS traffic lights are often synch'd with others, they all change at a specific time within a time cycle with related signals offset by seconds depending on traffic flow, mph, etc.
Most places are replacing these loops with video detection systems anyways... lower maintainence costs and overall better accuracy.

Now consider what it might be like if police had access to all those video feeds and were running face-matching software.... or even OCR for license plates.

( the ones I work on don't do that, so don't worry.... yet.)