Most of these magnet are small but don't let their size fool
you. They are very
powerful magnets. A 1/4" by 1/4" cube is capable of lifting 3 to 4 pounds in weight.
I have one that will lift a six-pound plumber's wrench. That magnet is only
1/2" diameter by 1/4" thick!
These magnets are very brittle. Do not allow these magnets to slam together.
If they do, they will shatter. Sending its pieces in all directions at
high velocity. Don't be surprised if you find a piece imbedded in your
valuable antique furniture, even in your eye.
If you allow these magnets come together and pinch
your skin, that really hurts and it's noooo fun.
The following experiments that you can do is easy. All you need are the materials
that are easily obtainable at your local home center.
Except for the Neodymium Magnet.
Get a 24 inch piece of "Type L" copper pipe . Type M will work
but Type L works
even better due to its heavier wall thickness. Remember, the thicker the wall the better.
Remove all burrs, inside and out at the end of the pipe after cutting. So you won't nick
yourself and prevent the magnet from getting caught at the end of the pipe.
A neodymium magnet the size of 1/4" by 1/4" cube. Other sizes will work as long as the
magnet fits inside the pipe without binding.
To demonstrate this experiment, hold the pipe vertical and drop
the neodymium magnet
into the pipe. You will notice that the magnet took some time for it to fall through the pipe.
Depending on size and how strong the neodymium magnet is. It would take about
3 to 8 seconds for it to fall through the pipe. If you take a piece of steel, the same size
as the magnet, it just simply falls right through!
Question: Why does the neodymium magnet takes so long for it to fall through the pipe?
The Answer: As the neodymium
magnet falls through the pipe. It's strong magnetic
field generates an electric current within the pipe called, Eddy Current. That, in turn,
produces a repulsion force against the magnet which creates a dynamic braking action.
This is why the magnet falls slowly through the copper pipe.
An aluminum pipe works almost as well, but copper works best -- try them both!
Copper conducts electricity better than aluminum does.
You will need a 24" piece of aluminum L-channeling. This can be
bought at home centers.
The thickness must be at least 1/8" or thicker. A small neodymium magnet which fits in
the channeling. You will also need a piece of aluminum, the same size as the magnet.
To do this experiment, hold the L-channeling with the bottom of
the V side down at an angle
of 45 degrees or a little steeper. Start with a piece of aluminum, place it in the
channel at the top and let it go. The piece of aluminum will slide right down the channeling.
Now, do the same with the neodymium magnet. You will notice that the magnet slowly
creeps down the channeling. This has the same effect as we did with the copper pipe.
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