Why did the left side of the left half remain unchanged at the N pole, and the right side of the right half turned out to be the S pole, but later it became the N pole? What is the law that causes the left magnetic pole order to change, while the right magnetic pole order changes. We can first assume that the magnet is originally N--S pole. After disconnection from the middle, it should be the N--S and N--S grades, but this is not the case. It becomes N--S and S--N. It is not material. Symmetrical? Why does the magnetic pole on the right change, but the left one does not change. In fact, no matter whether it is left or right, only one side has changed and the other side has not changed. The reason remains to be explored.
1. The direction of the magnetic induction line inside the ordinary strip magnet magnet is not as standard as indicated on the book, from one end to the other end, but an arbitrary diagonal line, not parallel to the three sets of edges of the magnet. Moreover, the magnetism of the magnet can still be considered to be uniform. This is because most of the magnets are cut directly from the magnetite ore in a random direction.
2, the magnet can be seen as six faces, three are the North Pole, three are the South Pole, and each of the two opposite faces is magnetically opposite.
3. After the magnet is disconnected from the middle, there is no such thing as magnetic reversal of a certain magnet. The magnetism of the magnet section is still opposite.
4. The two magnets are each magnetically identical to the four faces adjacent to the magnet cross section.
5. Due to similar reasons to the ring magnet, a repulsive force is generated between the sections.
6. Turn one of the magnets 180 degrees over. The cross-section of each of the two magnets and the corresponding faces of the four adjacent faces are opposite in magnetism, producing a gravitational force. So at this time the magnets are attracted.
7. There may be a strip magnet for demonstration. After manual magnetization, the direction of the magnetic line is standard from one end to the other, so that it can be directly attracted after breaking. But this should not be a general situation.