magnets and magnetic storage devices?

Question

I know you not supposed to put a stong magnet near magnetic tape/storage devises becasue is can erase the data but what is actually happening on the surface of the tape to cause this

Answer 1

The tape or other magnetic storage device uses the alignment of magnetic particles to store information. This can be digital, as in a floppy disk or analog as in an audio tape. In either case, the direction and magnitude of the field stored by the magnetic particles on the medium contains information.

When you place a magnet near the medium it realigns the magnetic particles and imposes a new field. The information that was contained in the arrangement and strength of the magnetic particles is destroyed.

Answer 2

the tape is magnetized in a binary format, which the vcr or reader is the dictionary for. By placing a mangnet near a tape you copletely destroy the binary encoded information making the tape useless