十万个为什么·科学启蒙30篇（1）

5 / 30

磁铁是如何工作的？

Magnets create invisible fields of force that attract certain metals like iron, nickel, and cobalt.
Every magnet has two poles: north and south—and opposite poles pull toward each other while like poles push apart.
These magnetic forces come from the motion of electrons spinning and orbiting inside atoms of magnetic materials.
In unmagnetized iron, these tiny atomic magnets point in random directions, canceling each other out.
When exposed to a strong magnetic field, many of those atomic magnets line up and reinforce one another.
Earth itself acts like a giant magnet, with its magnetic field stretching far into space and protecting us from solar wind.
Compasses work because their magnetized needles align with Earth’s magnetic field lines, pointing toward magnetic north.
Heating or hammering a magnet can scramble its aligned atoms and weaken or destroy its magnetism.
Some animals, including pigeons and sea turtles, have tiny magnetic crystals in their bodies to help them navigate long distances.
Unlike electric charges, magnetic poles always come in pairs—you cannot isolate a single north or south pole.