Britannica Sources used in this answer

Why do copper and silver move toward weaker parts of a magnetic field?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Learn about magnetic fields and the levels of particles, atoms, crystals, and domains — magnet Magnetic fields and the levels of magnetism of particles, atoms, crystals, and domains.

Copper and silver are classified as diamagnetic materials, which means they exhibit a weak, negative magnetic susceptibility.12

When these materials are placed in a nonuniform magnetic field, the external field induces a magnetic dipole moment within the atoms that is directed opposite to the applied field. According to Lenz’s law, this induced magnetic moment opposes the external field.2314

Because the induced magnetic moment is oriented against the external field, the potential energy of the material increases as it moves into regions of higher field strength. Consequently, to minimize their potential energy, copper and silver are pushed toward regions where the magnetic field is weaker. This behavior is a fundamental characteristic of all diamagnetic substances, where the induced magnetic field acts to repel the material from areas of higher magnetic intensity.5263