Connecting magnets in "series" = more force at the end?

[MitchJi]

Hi,

I'm trying to build a tool to roughly compare the paramagnetism of various sands (lava dust and crushed basalt and crushed granite).

I tried using one of these magnets:
http://www.lighthound.com/Magnetic-Spacer-for-Charging-14-x-14_p_1047.html

Magnetic Spacer for Charging 1/4" x 1/4"
Part Number LH14Mag

1/4" x 1/4" nickel plated neodymium disc magnet, poles on flat ends

I think its going to work better if I can get a stronger Magnetic force, at one end of the magnet. If I place 2 or 3 in "series" will I get more Magnetic force at the ends of the magnets? If so, how much (2 magnets = 2x the force?)?

Will the Magnetic force be proportionally stronger if I add 1 or 2 of these (same diameter, 1.5x longer), instead of the shorter magnets?:
http://www.lighthound.com/Magnetic-Spacer-for-Charging-CR2-or-14250-Battery_p_1048.html

Magnetic Spacer for Charging CR2 or 14250 Battery

Part Number LHCR2Mag
1/4" x 3/8" nickel plated neodymium disc magnet, poles on flat ends. Fits on positive end of CR2 battery for charging in CR-123a size chargers.

Thanks!

 

[Kingfish]

Welllll, from first-hand experience…
A buddy of mine last Friday purchased a couple dozen M48 ½ cm cube magnets and brought them to the watering hole on Friday Night and we were a bit like kids in a candy shop trying all sorts of experiments. He also purchased a very strong singular magnet with a pulling-force of 100 lbs.

Myths and deMyths
Logic says that stacking magnets should double, treble, quadruple power and so forth… but this will never be due to elementary physics.

Let’s presume each block is identical and having like charge. This makes the model convenient to discuss without a lot of extra maths.
Take one block magnet – and it has a power of 1. We don’t care how strong it is in reality; only that it has a unitary equivalent of One.
Add one magnet to it in series. The pulling force will never equal 2 x 1 because part of that force is utilized to attract itself to the magnet previously in line. The Load is split. The sum of the power or both magnets is actually less than the single magnet – which was the best case. Add more magnets, and you reduce the attractive power ever more so – incrementally. The force will never go to Zero, nor will it ever be stronger than a single magnet – so long as all magnets have the same pulling force.

It is better to create a single large magnet of the proportion and shape desired, and that will always have more pulling power than an array of individual magnets.

There’s a math theorem that explains this well – but I am at a loss to remember.

So to repeat, adding magnets in series creates measurable losses relative to creating a single magnet of the same power.

Ever wonder why a broken magnet pulls less? Now you know :wink:
~KF

 

[r3volved]

It is better to create a single large magnet of the proportion and shape desired, and that will always have more pulling power than an array of individual magnets.

this

Or make an electro magnet?

 

[liveforphysics]

You can't make the magnet stronger, but you can make configurations of them that shape the field to be more in the direction you care about the field being.

 

[Kingfish]

You can't make the magnet stronger, but you can make configurations of them that shape the field to be more in the direction you care about the field being.

Yes, exactly - good point
Example: Halbach Array.

In flux, KF

 

[MitchJi]

Thanks LFP And KF!