I would like some advice about magnetism from the specialists in
the physics groups.
My kitchen table experiment seems to show that ferrous material
near a magnet weakens the magnetic flux of a fixed point between
From time to time I need to erase some recordings made on tape
cassettes. I don't have a bulk eraser so I erase the tape in the
machine by recording over it in real time.
That's slow! I often get a much faster result by using a strong
neodymium magnet from a hard disk drive and wiping it over the
surface of the tape cassette. But sometimes this method does not
fully erase the tape 100%.
So I figured that I could hold the tape in front of some ferrous
metal sheet (like the stove, the side of the microwave oven, etc)
and then put the magnet ontop of the the tape in order to let the
metal sheet focus the magnetism and so in this way subject the
tape to a STRONGER magnetic field.
However I tested this idea at home using a magnetic compass and a
scrap of ferrous metal. My simplistic experiment showed that the
ferrous sheet behind the compass REDUCED the needle deviation due
to the neodymium magnet.
Is this result correct? Or is my experiment crap?
Or is it my physics which is crap because I thought the ferrous
metal on the other side of my tape (or compass) would subject it
to a stronger magnetic field.