Magnets

[rae]

Hi All,

I'm looking to buy magnets that are suitable for Yr11 & 12 physics and also electromagnet work for Yr10. I've looked in a couple of catalogues and am now very confused, there are so many types. Does anyone have any tips on what to look for and what would be suitable?
Any help gratefully accepted.

Lorrae

[Ian]

Hi All,

I'm looking to buy magnets that are suitable for Yr11 & 12 physics and also electromagnet work for Yr10. I've looked in a couple of catalogues and am now very confused, there are so many types. Does anyone have any tips on what to look for and what would be suitable?
Any help gratefully accepted.

Lorrae

Hi Lorrae,
I guess it depends a bit on exactly what you want to do with the magnets, but I have found that the plain old garden variety "Alnico Bar magnets" are good for most things. You can set them up on a flat surface with a sheet of paper and see field lines, by sprinkling iron filings on the paper, you can sit one on a watch glass to make a compass or to observe attraction and repulsion, you can pass them through a coil to see electromagnetic induction, use them to pick up paper clips or to magnetise a sewing needle. Demonstrate "Lense' Law". I have a couple set up permanently, one above the other with a wire "swing" suspended between them to demonstrate electromotive force. You can use them to power a home made electric motor,Our junior kids use them to separate iron filings from a mixture of sand, and they work well for holding notices to the fridge

Having said that, my favourite is a neo molydynium disk magnet that we drop through an aluminium tube to demonstrate "Eddy Currents" It takes about half a minute to fall one metre through the tube in sloooooow motion!

I hope this helps.

regards
Ian

[Mother]

Hi ya all
Whilst on the subject of magnets,and pardon my stupidity.I have lots of bar magnets and most of them don't have as much strength as I think they should have.How do I strengthen them????
Mother

[Labbie]

Q-stores had a stall at st Marys last year. I am sure it was q-stores and they showed us how to do it. North to North with a re-Magnet. Perhaps some one else can remember the stall??

Magnets should always be stored with their keepers, when not in use.

[ri]

Hi All,
the people at Walchope where we bought our bar magnets years ago, have a service where they re-magnetise them, paint them and supply new spacers and keepers if needed. All at a very reasonable price,
Cheers,
~Robyn