If the magnetic field changes, the walls move, changing the relative sizes of the domains.

This is because the gravitational field changes across the middle of a body (the diameter).

The geomagnetic field changes on time scales from milliseconds to millions of years.

Because the Earth's field changes over time, the maps must be kept up to date for accurate navigation.

The direction of the field changes with the frequency of the cavity.

Answers to the following questions are being sought: Why does the magnetic field change with an eleven-year cycle?

The Earth's magnetic field changes due to solar flares and various atmospheric conditions.

This field change can be detected by a surrounding coil.

When a field travels across to different media, the properties of the field change according to the various boundary conditions.

The kinetic energy of the particles is increased by a constant amount per field change (one half or a whole revolution).