Hello, just out of curiousity I was making sparks(shorting a 9v 500ma dc wallwart) on a neodynium magnet and I noticed the spart is many times larger than if I had just touched the two wires together
i tested the current and it draws 2.5a dropping the voltage down to around 3 volts
I also noticed that the larger sparks(in length) also happen when sparking to anything iron, but the thickness is not as large with the magnet being 3times bigger and brighter
this has nothing to do with arduino but I can't find anything on the net, anyone know why this happens? At first I thought maybe the magnetic field does it, so I tried both poles with the same result
then I figured its the material and I found the iron does similiar but not as spectacular, but im wonderingif perhaps the iron being as magnetically unique magnifies the magnetic field and causes the spark because of the magnetic field
Any thoughts would be appreciated
never thought about it but most neodynium magnet's I have seen are covered in chrome which flakes easier?
My guess would be it's the resistance value of the material. Get your digital multimeter and measure it's resistance. If you don't own a multimeter, go buy one right now. You aren't allowed to post on the arduino site if you don't own and know how to use a meter. 
Cant be resistance since the leads sparking alone will be least resistance
And the chromes mostly gone already but same results
winner10920:
Cant be resistance since the leads sparking alone will be least resistance
And the chromes mostly gone already but same results
Not sure I understand that, but shorting out battery with least resistance doesn't necessarily result in most sparking. Don't confuse current flow with sparking, they are different things. Have you measure the resistance yet with your meter I told you to go buy?
Steelwool sparks really well but steel has higher resistance then copper.
Lefty
I've pretty sure that you can chalk it up to different metals with different surface properties. The "sparks" you get when brushing two pieces of wire together are mostly little pieces of burning metal, dislodged by the heat of the high current. Not at all like the high-voltage sparks you'd get from a Marx generator or something.
Iron burns really nicely. Copper and Nickle, rather less, I think...
Im talking about when touching and releasing the wire, those sparks
And i mean that with just the leads resistance there is less spark than with the magnet,
And that makes sense, the flying debris from the specific material
But wouldnt all those debris( having their own north and south) turn around and attract to the magnet? I dont see any dust or debris
I dont see any dust or debris
Consumed in the fire of the sparks. You get that meter yet?
you can demagnetize stuff by whacking it with a hammer, I would gather a small violent explosion could have the same effect.
also I think lefty wants you to get a meter ... I agree
Lol I have one, aka the 2.5 @3v short and the rated 9v @ 500ma
but im @ school right now and can't test it
and is de magnetized neodynium not attracted to a magnet like iron?
Lol I actually have 3, even a LRC one, I doubt the neodynium has even an ohm, a nickel sized metal circle I imagine has less resistance than the 18 gauge 4ft long leads of stranded copper, plus the diodes
And interestingly I found out neodymium magnets are 70% iron, wonder how that changes it to be 3x more spark than iron and 30x more than copper
Ps, meter only goes down to 1ohm, and the magnet is below that,
Osgeld:
you can demagnetize stuff by whacking it with a hammer
I can confirm this. I have whacked several of my fingers, multiple times, and none of them are magnetic.
The easiest way to demagnetized neodymium magnets is to heat them up past their max rated temperature. Many R/C modelers were finding that they were losing their neo magnets if they ran their brush-less motors beyond their max rated current thus overheating the magnets. You can now buy neodymium batteries with different max temperature ratings.
Lefty
The other ingredients (Neodynium and Boron) both burn better than iron...
But it's more likely to be the plating material than the magnetic material itself.
Also, NeFeB has a relatively low conductivity (worse than nichrome, for instance), so localized heating might be greater than with a more electrically and thermally conductive material...
It would be an interesting experiment to try to isolate the factors that lead to difference in sparking behavior.
But difficult to come up with a specific methodology...
If my phone allowed me to upload a picture of this magnet of mine, you will doubt that it can be anything to do with plating(mainly it is completly sparked away), 3x9v batteries I found is my current power supply and with the 27 volts I am getting quite amazing sparks and arcs(arcs probably from the 200 turn coil of wire im using to touch to the magnet or atleat that was my plan)
it actually is lighting up a decent amount maybe ill get some pictures to upload on the computer
still much more sparks relative to a dead short spark
Pictures or it didn't happen.
Video or it didn't happen
maybe the magnetic field helps to ionize >?