CJT wrote:

I certainly recall doing the same thing. I think there was even a kit
in a little red box that had the wire, etc. and an instruction sheet;
the box formed the base.

I remember building a variation as a child, suspended a bit of stiff wire
off a hook, with the bottom dipped into a little mercury in the bottom of
one of mums pans (discovered interesting things about amalgams as well that
day - Physics AND Chemistry), pop a small disk magnet into the bottom of
the mercury and hook up a power supply - NOT A CAR BATTERY, IT BOILS THE
MERCURY (I speak from experience).

Probably best done in a well ventilated space.

Regards, Dan.