I actually did this when I read about it on this NG. I bought a few rare
earth magnets, took 3 of 'em and stacked them up (be careful, they pull
together so hard it can pinch) and dropped them into a straight piece of
1/2" copper pipe. Actually, it's best to take a slug of steel and drop it
down first. Plunk. Then drop the magnets. They sort of float down gently,
taking several seconds. It's fascinating to watch.

I took the whole shebang to my son's physics teacher and told him "here's
a great classroom demo". He thought so too and I'll bet that gets shown
every year at the local junior high for awhile.

GWE

Don Bruder wrote:

In article ,
Trevor Jones wrote:


Wanna baffle a lot of people? Drop a rare earth magnet down a piece of
aluminum pipe. Have them explain to you why it drops the way it does.


OK, having seen this type of mention twice in this thread now, and
lacking the ability to perform the "experiment" (Got some HDD magnets,
but apparently nothing suitable to drop them down - they just slid down
the aluminum flashing I tried. Big fat hairy deal...) I gotta know:

What happens? (Not the physics, electrical theory, etc, just the
physical "What am I supposed to see when I do it?")