Ok, ready for another variable?
http://en.wikipedia.org/wiki/Demagnetizing_field
http://en.wikipedia.org/wiki/Degaussing
Anytime you talk about anything electrical, magnetic, physics fields, forces, poles you are going to find variable tuning. What makes this world work (balanced) is the constant "tuning" that takes place as a continuum. Pendulum, action/reaction, time, space, motion, exchange, flow are all parts of a balancing (tuning) system that keeps billions of billions of variables in check and working. This is physics and this is how we get from this moment to the next. Physics is not a snap shot, it's not even a motion picture. Physics is an interactive hologram of on-going perpetuation. Energy continues or transforms. It always was, is and will be.
There are systems in place that exist because of the need for exchange. These systems are called forces, and none of them are dead without motion. Even a standing wave is traveling when you pull back enough to see the world spin. Science does what it can to create theoretical snap shots for us to slow things down enough to study, but they are not practical application. The only way to turn theory into proof, is by doing, and doing with repetition. To this end, is why science is made of sums and averages.
Is there a defined zero in demagnetizing? Science says not really, but more of one of my favorite terms a "variable" degree of fair exchange.
michael green
MGA/RoomTune
http://tuneland.techno-zone.net/