Hello All,
I was setting a few rare earth magnets in a piece I just finished when
my brother stopped by and told me about this phenomenon you can
perform with one of these magnets and a length of copper pipe. (and
no, this is not X-rated!).
I took a 12 inch length of 3/4 inch copper and holding it vertically I
dropped the magnet through the pipe and was able to reach down with
the same hand and catch the magnet. You can watch it fall so
slowly.
The magnet causes an electrical field which must generate its own
counter EMF, much like the same forces that exist in an electric
motor.
So, if you use any of thes powerful magnets as door latches in your
woodworking projects you can also impress the kids and your pets with
this cool trick.
Read you all later,
Marc

On Mar 1, 9:17*pm, marc rosen wrote:
Hello All,
I was setting a few rare earth magnets in a piece I just finished when
my brother stopped by and told me about this phenomenon you can
perform with one of these magnets and a length of copper pipe. *(and
no, this is not X-rated!).
I took a 12 inch length of 3/4 inch copper and holding it vertically I
dropped the magnet through the pipe and was able to reach down with
the same hand and catch the magnet. *You can watch it fall so
slowly.
The magnet causes an electrical field which must generate its own
counter EMF, much like the same forces that exist in an electric
motor.
So, if you use any of thes powerful magnets as door latches in your
woodworking projects you can also impress the kids and your pets with
this cool trick.
Read you all later,
* * * * * * * * * * * * * *Marc

That is very cool !

Randy
http://nokeswoodworks.com

On Mar 2, 9:13*am, Maxwell Lol wrote:
marc rosen writes:
The magnet causes an electrical field which must generate its own
counter EMF, much like the same forces that exist in an electric
motor.

* * * * They're called eddy fields.
Because energy is created, energy elsewhere has to be reduced (speed).

Funny, my brother's name is Eddie.
Marc

On Mar 2, 6:49*am, marc rosen wrote:
On Mar 2, 9:13*am, Maxwell Lol wrote:

marc rosen writes:
The magnet causes an electrical field which must generate its own
counter EMF, much like the same forces that exist in an electric
motor.

* * * * They're called eddy fields.
Because energy is created, energy elsewhere has to be reduced (speed).

Funny, my brother's name is Eddie.
* * * * * * * * * * * * * * * * * * * * * * * * * Marc

I bit and tried , pretty cool

On Sat, 1 Mar 2008 19:17:52 -0800 (PST), marc rosen
wrote:

Hello All,
I was setting a few rare earth magnets in a piece I just finished when
my brother stopped by and told me about this phenomenon you can
perform with one of these magnets and a length of copper pipe. (and
no, this is not X-rated!).
I took a 12 inch length of 3/4 inch copper and holding it vertically I
dropped the magnet through the pipe and was able to reach down with
the same hand and catch the magnet. You can watch it fall so
slowly.
The magnet causes an electrical field which must generate its own
counter EMF, much like the same forces that exist in an electric
motor.
So, if you use any of thes powerful magnets as door latches in your
woodworking projects you can also impress the kids and your pets with
this cool trick.


There's a show on the Discovery Channel called "Smash Lab" where they
make completely impractical solutions to various things. One episode
they made a fire escape out of a sled with some serious magnets riding
down an aluminum bar on the outside of a 6 story building. That was
one of the few things they've done that actually worked. Complete
madness, but it worked.


-Leuf

Hello All,
I was setting a few rare earth magnets in a piece I just finished when
my brother stopped by and told me about this phenomenon you can
perform with one of these magnets and a length of copper pipe. (and
no, this is not X-rated!).
I took a 12 inch length of 3/4 inch copper and holding it vertically I
dropped the magnet through the pipe and was able to reach down with
the same hand and catch the magnet. You can watch it fall so
slowly.
The magnet causes an electrical field which must generate its own
counter EMF, much like the same forces that exist in an electric
motor.
So, if you use any of thes powerful magnets as door latches in your
woodworking projects you can also impress the kids and your pets with
this cool trick.

This really caught my attention, so here is a link...

http://en.wikipedia.org/wiki/Neodymium_magnet

--

-Mike-

Mike Marlow wrote:

Hello All,
I was setting a few rare earth magnets in a piece I just finished when
my brother stopped by and told me about this phenomenon you can
perform with one of these magnets and a length of copper pipe. (and
no, this is not X-rated!).
I took a 12 inch length of 3/4 inch copper and holding it vertically I
dropped the magnet through the pipe and was able to reach down with
the same hand and catch the magnet. You can watch it fall so
slowly.
The magnet causes an electrical field which must generate its own
counter EMF, much like the same forces that exist in an electric
motor.
So, if you use any of thes powerful magnets as door latches in your
woodworking projects you can also impress the kids and your pets with
this cool trick.


This really caught my attention, so here is a link...

http://en.wikipedia.org/wiki/Neodymium_magnet


I have several of those that I took out of dead harddrives. They
are great for sticking very important floppy disks on the fridge
so that you don't lose them.

If you have two, you can place one on the palm of your hand and
the other on the back of your hand and they will hold themselves
to your hand.

They will also cause nasty blood blisters if you get your finger
caught between them.

--
Robert Allison
Rimshot, Inc.
Georgetown, TX

On Sat, 1 Mar 2008 19:17:52 -0800 (PST), marc rosen
wrote:

Hello All,
I was setting a few rare earth magnets in a piece I just finished when
my brother stopped by and told me about this phenomenon you can
perform with one of these magnets and a length of copper pipe. (and
no, this is not X-rated!).
I took a 12 inch length of 3/4 inch copper and holding it vertically I
dropped the magnet through the pipe and was able to reach down with
the same hand and catch the magnet. You can watch it fall so
slowly.
The magnet causes an electrical field which must generate its own
counter EMF, much like the same forces that exist in an electric
motor.
So, if you use any of thes powerful magnets as door latches in your
woodworking projects you can also impress the kids and your pets with
this cool trick.
Read you all later,
Marc

I bit and tried too. I used a 3/4"-dia copper pipe, 18" long, and a
stack of 5 rare earth magnets, 0.70"-dia or thereabouts. It takes 6
seconds for the stack to fall through the pipe. They float leisurely
down the middle of the pipe without touching the sides.

Too cool

-Zz

* * * * They're called eddy fields.
Because energy is created, energy elsewhere has to be reduced (speed).

Funny, my brother's name is Eddie.
* * * * * * * * * * * * * * * * * * * * * * * * * Marc

I bet if you drop him down a big copper pipe, Eddie wouldn't fall as fast
as a piece of wood either.

Thanks Maxwell,
You made me laugh with a mouthful of coffee this morning. That was
really funny and I'm passing this on to Eddie.
Marc

On Mar 2, 8:13 am, Maxwell Lol wrote:
marc rosen writes:
The magnet causes an electrical field which must generate its own
counter EMF, much like the same forces that exist in an electric
motor.

They're called eddy fields.
Because energy is created, energy elsewhere has to be reduced (speed).

The concept is generally know as the eddy CURRENT. The changing
magnetic
field due to the motion of the magnet induces an eddy current in the
pipe; the eddy
current in turn induces a magnetic field the same way any current old
induces a magnetic field. There is a relative minus sign so the field
due to the eddy current opposes
the field from the magnet -- no perptual motion machines. There is
nothing special about the fields.

Energy isn't created nor lost. The gravitational potential energy of
the magnets is converted into
kinetic energy and (presumably) heat in the pipe. If the pipe has
poorer conductivity the speed restriction
should be less dramatic -- anybody got an aluminum pipe? If you
repeat the exercise with a copper pipe but put a slit down one side
what happens?

hex
-30-

marc rosen wrote:
Hello All,
I was setting a few rare earth magnets in a piece I just finished when
my brother stopped by and told me about this phenomenon you can
perform with one of these magnets and a length of copper pipe. (and
no, this is not X-rated!).
I took a 12 inch length of 3/4 inch copper and holding it vertically I
dropped the magnet through the pipe and was able to reach down with
the same hand and catch the magnet. You can watch it fall so
slowly.
The magnet causes an electrical field which must generate its own
counter EMF, much like the same forces that exist in an electric
motor.
So, if you use any of thes powerful magnets as door latches in your
woodworking projects you can also impress the kids and your pets with
this cool trick.
Read you all later,
Marc

It works! Also aluminum tubing slows it down, but not as well as
copper. But steel tubing slows it most of all.

--
Gerald Ross
Cochran, GA

I never remember a face, but I always
forget a name.

On Mar 5, 9:24*pm, Gerald Ross wrote:


. But steel tubing slows it most of all.


I bet

Robatoy wrote in news:3b1e2c30-89f1-4369-8918-
:

On Mar 5, 9:24*pm, Gerald Ross wrote:


. But steel tubing slows it most of all.


I bet

What about stainless?


--
Best regards
Han
email address is invalid

Han wrote:
Robatoy wrote in news:3b1e2c30-89f1-4369-8918-
:

On Mar 5, 9:24 pm, Gerald Ross wrote:


. But steel tubing slows it most of all.


I bet

What about stainless?


Depends. Some SS is attracted by these magnets, such as SS knife
blades. I had a similar length of stainless pipe, but a little larger
than the diameter of the other two. It slowed down the magnet less
than the aluminum. I was using a spherical magnet from Lee Valley.

I think the braking depends on the electrical conductivity, so
theoretically a silver or gold tube would really slow it down. I
didn't have any lying around the shop, so couldn't test it.

--
Gerald Ross
Cochran, GA

I pray for boredom but it never comes.

"Gerald Ross" wrote:

Depends. Some SS is attracted by these magnets, such as SS knife
blades.

SFWIW, if it is magnetic, it isn't stainless.

300 series S/S is not magnetic.

316L is the premium grade for most applications.

304 is probably the most common grade.

400 series is not truly stainless since it still has some austinite,
is magnetic, and is used for things like springs, knife blades, etc
that need to be heat treated.

Lew

On Mar 6, 11:48*am, Gerald Ross wrote:


I think the braking depends on the electrical conductivity, so
theoretically a silver or gold tube would really slow it down. I
didn't have any lying around the shop, so couldn't test it.

Aluminium only conducts about 2/3rds as well as copper. Therefore, to
match the electrical conductivity of your copper tube, the aluminium
one should have a wall thickness of about 30+% more than the copper
tube's. BUT, that increase in thickness, only manifests itself at a
further distance from the magnet, so even if the conductivity were to
be equal, the copper would still have an advantage. Especially if the
copper tube was manufactured by the Monster Cable people. But then
again, I could be talking ****.

r

Lew Hodgett wrote:
"Gerald Ross" wrote:

Depends. Some SS is attracted by these magnets, such as SS knife
blades.

SFWIW, if it is magnetic, it isn't stainless.

300 series S/S is not magnetic.

316L is the premium grade for most applications.

304 is probably the most common grade.

400 series is not truly stainless since it still has some austinite,
is magnetic, and is used for things like springs, knife blades, etc
that need to be heat treated.

Lew



Not being a metallurgist, all I can say is it has "Stainless" on the
blade.

--
Gerald Ross
Cochran, GA

"Gerald Ross" wrote:


Not being a metallurgist, all I can say is it has "Stainless" on the
blade.


Then it must be trueG

Lew

The thickness of the metal matters. The thicker it is, the better the
braking effect. If you don't have a copper tube (especially one that's
close to the dimensions of your magnet), but you do have a flat aluminum
plate, try inclining it steeply and sliding the magnet down. Try different
thicknesses of metal if you have them and you'll see.

- Owen -

"Robatoy" wrote in message
...
On Mar 6, 11:48 am, Gerald Ross wrote:


I think the braking depends on the electrical conductivity, so
theoretically a silver or gold tube would really slow it down. I
didn't have any lying around the shop, so couldn't test it.

Aluminium only conducts about 2/3rds as well as copper. Therefore, to
match the electrical conductivity of your copper tube, the aluminium
one should have a wall thickness of about 30+% more than the copper
tube's. BUT, that increase in thickness, only manifests itself at a
further distance from the magnet, so even if the conductivity were to
be equal, the copper would still have an advantage. Especially if the
copper tube was manufactured by the Monster Cable people. But then
again, I could be talking ****.

r

For those with a less than stellar table saw, a rare earth magnet on its
side will pass the "nickel test" every time.......plastic or aluminum saws
obviously excluded. Rod




marc rosen wrote:
Hello All,
I was setting a few rare earth magnets in a piece I just finished when
my brother stopped by and told me about this phenomenon you can
perform with one of these magnets and a length of copper pipe. (and
no, this is not X-rated!).
I took a 12 inch length of 3/4 inch copper and holding it vertically I
dropped the magnet through the pipe and was able to reach down with
the same hand and catch the magnet. You can watch it fall so
slowly.
The magnet causes an electrical field which must generate its own
counter EMF, much like the same forces that exist in an electric
motor.
So, if you use any of thes powerful magnets as door latches in your
woodworking projects you can also impress the kids and your pets with
this cool trick.
Read you all later,
Marc