why does the magnetic force go through aluminum foil?

Aluminium is a material that doesn't influence a magnetic field. Magnetic fields pass through Aluminium (and most materials - including many metals) without interaction because they are not magnetic materials.

A magnetic material will actually provide an 'easier' pathway for magnetic fields. These materials support the formation of magnetic fields by aligning their own magnetism with the field's (an alignment of their magnetic 'domains'). Where this happens the magnetic field follows (goes with) the magnetic material instead of going through the air .. so the field is diverted rather than blocked.

The strongest magnetic materials belong to a group called ferromagnetic - because they contain a high proportion of iron. Iron itself increases the strength of a magnetic field by about 700 times compared to air - no wonder magnetic field lines are diverted to follow a path through iron rather than through air.

Is Aluminium Foil Magnetic

modern passing nevertheless a cord creates a magnetic field around it. If a chew of cord passes by a magnetic field reducing throught the line of the sphere, a modern would be produced in the cord.

Because it is conductive and very thin. If the aluminum was very thick...say and inch or more..it would not go through unless the magnet was very powerful.

Aluminium is a nonferrous metal.