Magnetic braking of magnets sliding along a sloped aluminum surface

[lumen]

I agree with TK!
I just ran several tests by putting a large magnet behind the aluminum sheet (south facing the back of the sheet) at a distance just far enough to change the compass to point north in the opposite of earths direction. (north now towards the sheet)

Results:
The North side of the sliding magnet would hang as usual UNTIL it gets just below the large magnet, then it would fall away!

Starting at the fall away point NOW, the south side would hang for the rest of the slide.

I believe it is the inclination angle of the earths lines of flux causing the effect as TK has said.

[maw2432]

Just to be sure that we are all on the same page wrt magnet pole naming conventions:

The normal convention is that the Earth's magnetic pole in the North of Canada is a South magnetic pole.
The polarity of the compass needle magnet is marked correctly. The compass needle's North pole points to the Earth's South magnetic pole which is in the Arctic northern hemisphere.
Any magnet suspended like a compass will have its North pole pointing to geographic North.
The North pole of a magnet will Repel the North-seeking compass needle.
Flux lines are to be thought of as coming OUT of the North pole and going IN to the South pole of any magnet.

Dip or inclination refers to the angle at which the lines make with horizontal at any location. Horizontal = 0 degrees dip, and the dip is positive in the Northern hemisphere and negative in the Southern. In my location the dip angle is around 70 degrees--quite steep, only 20 degrees from vertical.

I have had one reliable report from Australia that has the opposite pole coming off, as predicted by the dip hypothesis. I also have a report that the polarity of coming off can be affected by doing the experiment in the field of a set of Helmholz coils, and I can confirm that--I didn't have time to tune our coils precisely but just jamming the juice in does indeed reverse or modify the effect, depending on orientation of the slide.

Still, I think the dip hypothesis has not been conclusively proven, and more data will be gathered over the next week or so.

Funny thing TK,   all the text books say the Earth's Magnetic North Pole is the one in North Canada. 
I do not understand what you are saying when you say the above.   Maybe you made a  typo?   

http://en.wikipedia.org/wiki/North_Magnetic_Pole
http://geography.about.com/od/learnabouttheearth/a/northpole_2.htm
http://www2.scholastic.com/browse/article.jsp?id=4616


Bill

[lumen]

Because opposite poles attract, the Earth's North Magnetic Pole is therefore physically a magnetic field south pole because a north pole attracts to it.

After the last tests I did I started to think how much does the earths field actually affect things and I was very surprised!

Dropping a 1" Diameter x 1/4" thick N50 only 12", it will flip over every time with north down. I live about 45 degrees north.

You can do this easily in your hand, just place it flat in you hand with north side up and quickly lower it about 12" and bang! north down. If you watch it real close, you will see it flipping.

If you start with north down, it will stay north down. This should be the opposite in Australia.

[BEP]

Just to be sure that we are all on the same page wrt magnet pole naming conventions:

I think the above is the MAIN point. You can name poles anything you want as long as everyone discussing uses the same meanings. Either way can be correct but TK's description is the norm for pole naming.

[BEP]

I agree. Earth's field is very very tiny compared to that of a neo and it will not even notice it.

Be careful on wording. A 'very strong' neo needs to be within several inches to have an effect but the Earth's magnetic pole can be X miles away and have the same effect. We call the Earth's magnetic field weak?

If this effect is due to an external field, then placing a magnet nearby should alter it, as you say.

I wouldn't call it 'external'.

Having Helmholtz coils show change in effect does not surprise me. Now, having a Maxwell coil cause the same effect change would surprise me.

So, does everyone now see that Eddy doesn't need to play in this game?