> Show them magnet tricks.
>     =3D=3D  two magnets that can't be pulled apart but can be slid apart.

Get a couple of heavy gauge wires (e.g. 16 gauge), and hang them from a tes=
t tube stand or some other means so they can swing freely with electrical c=
onnections to both ends. Now with a suitable high current power supply conn=
ect the wires so the currents in them can be going the same direction or op=
posite directions to show magnetic attraction and repulsion due to the curr=
ent flow. Can be quite a nice demonstration with the wires hanging about an=
 inch apart and effectively short circuiting a 6V motor bike battery ... yo=
u may like to have a current limiting resistor to limit the current to a co=
uple of amps ...

When I was asked to set this up as a lab boy at secondary school, we used a=
 bath of mercury as the bottom connection to the hanging wires, which resul=
ted in sparks when another wire was dipped in to make the circuit connectio=
n, with a resulting small puff of smoke. Somehow I don't think H&S rules wo=
uld allow one to use a mercury bath these days ....



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