Re: Questions about magnets.
 

Use some kinda of ferrous casing around what ever you want to protect. This way the magnetic field will go around the outside of the case. This is how hard drives are protected. If you don't know what I am talking about, go look at he magnetics field of a ring magnet. Or go put a magnet up to a steel washer and sprinkle iron filings on it to visualize the magnetic field.

we are studying this in physics right now, so someone please correct me if I am wrong. This is just what I have been taught, No experience with this.

Re: Questions about magnets.
 

Well, Lord is located near us, and at a career fair I got to play around a bit with it. I cannot imagine a way that you could make a CVT with it, but a magnetic clutch is very feasible. FIRST or otherwise, it'd make for some nice shifting tranmissions!

Re: Questions about magnets.
 

As already said, every magnet has a north and south pole. One of the major searches underway in nuclear physics is for "the magnetic monopole": If one can be found, it will tie up some loose ends in the grand unification theory, helping equate gravity to magnetism (and therefore electricity). Can you say anti-gravity??

Strongest means magnetic flux density. The absolute strength is the same at both ends, kind of like the current in a simple DC circuit, but you can modify the flux density (measured in Gauss) by physically changing the shape of the magnet, or channeling the magnetic flux to a point. (For example, make an electromagnet from a nail. The pointy end will appear 'stronger' than the flat end)

Mu metal is indeed a great magnetic shield. For cheap, find a TV and take the metal shielding near the picture tube*. The better a material 'conducts' magnetism, the better of a magnetic shield it is - just like electrical shielding. "Shielding" just gives the magnetic (or electrical, or whatever) field an easier place to travel, and so you direct it around whatever object you are shielding. Steel is not too bad a shield, for the cost.

* Warning: The picture tube has high voltage, and acts like a capacitor to store it for quite a long time. Stay the heck away from the high voltage wire to the picture tube (which looks kind of like a spark plug wire) and any connectors to same.

Buying magnets: American Science & Surplus, plus those already mentioned.

Don

Re: Questions about magnets.
 

I have to throw in my 2 cents here. It is almost impossible to remove the degaussing shield from a picture tube without removing the anode lead. The picture tube can hold a charge for months after it has been unplugged. Depending on the design that voltage can be up to 40kV. In addition, the tube has an extreme vacuum and if handled improperly, can launch tube internals at lethal speeds should the tube break.

Re: Questions about magnets.
 

Al's comment on the High Voltage needs to be taken seriously, and I perhaps underestimated it in my post above.

While I do not disagree with Al's warning on tube vacuum, I have some comments:

It's not that the tube is under such a high vacuum, but that there is such a huge volume of it. A regular light bulb has the same grade of vacuum, but in just a tiny volume.

On the other hand, in a former job, we used to break picture tubes all the time for testing, and we never had a problem like that. Yes, raw phosphor material blasted into the air (Warning: Poison!) , glass shards at surprisingly high velocities, loud noise... but no internals.

Don

Re: Questions about magnets.
 

Dan,
There is a reason the front of the tube is tempered and/or safety glass. Having worked in a TV factory it is surprising to see an electron gun sucked through the tube when the neck breaks.