Magnetic field viewer


Uploaded by wbeaty on 18.06.2007

Transcript:
Here's a way to see magnetic fields
in three dimensions even!
Here's a bottle of baby oil
but it's SPECIAL baby oil.
Big old magnet. You could use a loudspeaker magnet.
This one's out of a microwave oven.
See what's going on?
It's full iron filings.
And here's how to make one.
Steel wool.
You can unwrap
wads of steel wool.
So I use the, is it the...
four-zeros or four-XXXX, whatever,
the ultra-fine steel wool.
That settles out
most slowly.
But you might want to try
thicker steel wool
that's easier to see.
Trim off
all the extra fibers
so you have
about an inch wide
of steel wool.
And then (let's get rid of
all of the junk!)
...then very carefully cut across
the trimmed end, and
you want to cut up about half a square inch,
so; this is an inch wide,
so I'm going to cut up
about half an inch of it.
Let's get all the long fibers out of there.
Cutting it at, um...
maybe every sixteenth inch, very carefully.
And you don't want long fibers,
you want lots of little tiny ones.
So when you're done that's maybe half a teaspoon?
Get some baby oil.
And I went to the store and found one where
the label is only on one side
and it's easy to peel off.
So you can get rid of the label that's there
and then spray it with white spray paint
for a nice uniform background.
And that's the
three-D magnetic viewing Cell.
You can get these from physics catalogs
built out of plexiglas
for a couple hundred bucks too!
There. Now I did it and was careful.
Ah there's still a few long ones
so use the scissors to
drag out any long,
long fibers.
Ooo, it looks like my scissors got magnetized.
AND... wad 'em all up
and dump it in the baby oil.
Paper barrier!
Now if it clumps,
then you've got too much.
I'm going to get the bubble out, here.
If I squeeze carefully,
until it just gets some oil out.
There's my wad.
Nope, bubble came back.
Not tight enough.
Let me try again,
get the bubble out.
That looks like it worked.
This is was with the
not-so-fine steel wool
and it tends to settle out faster.
There's the magnet field pattern!