A magnet will not attract a aluminum bar, but if you have an electromagnetic field made by an transformer it will interact.Why is that?Why iron is attracted and wood is not?
Aluminum is not a magnetic material and will not be affected by stationary magnets. However, if a changing magnetic field is present, an electrical voltage will be induced in the aluminum ring and an electric current will flow as a result. This current will produce a magnetic field which will interact with the externally produced magnetic field. The key here is a changing magnetic field - because the voltage induced in the aluminum ring will be proportional to the rate of change of the field. If an aluminum disk is passed between the poles of a powerful magnet, eddy currents will be induced in the aluminum producing a magnetic field that will tend to retard the motion of the aluminum relative to the magnet. The changing field in this case is due to the motion of the aluminum. Iron is attracted to a magnetic field because it is a ferro-magnetic material. Wood is not a magnetic material, and it is not an electrical conductor, so it will not behave as aluminum does in a magnetic field.
