This video and animation illustrate Faraday's Law.
As a permanent magnet is moved back and forth in the
vacinity of a coil of conducting wire, a current is
induced in the coil (as measured by the ammeter in the
video). This induced current is proportional to the
rate of change of magnetic flux through the enclosed
area of the coil, and flows in such a direction as to
generate a field whose change in flux opposes that change.
In the animation, we show the evolution of the magnetic
field during this process.