Why a broken magnet gets two ends
A bar magnet’s north and south poles are not separate substances stuck to its ends. Magnetism in materials such as iron comes from tiny magnetic moments associated mainly with electrons. In an ordinary magnet, many of these moments line up, giving the material a strong overall magnetic direction.
That direction runs through the whole bar. When you snap it, the aligned moments remain in each piece. The newly exposed faces become opposite poles, so each fragment has its own north and south end. Break a fragment again, and the same pattern repeats—not because the pieces somehow grow new poles, but because the magnetic arrangement continues through each smaller piece.
The field has no loose ends
A useful way to picture the result is through magnetic field lines. Outside a bar magnet, they run from its north end toward its south end; inside the magnet, they continue back around, forming closed loops. Cutting the bar changes the shape of those loops and creates new pole-like ends at the cut, but it does not leave a field line terminating at an isolated north or south pole.
That differs from electric charge, where a positive or negative charge can exist by itself. Physicists call a lone magnetic pole a magnetic monopole. It is a possibility in some theories, but none has been confirmed. Until one is found, every familiar magnet—from a compass needle to a broken refrigerator magnet—shows the same practical rule: split the magnet, and you split it into smaller north–south pairs.
