Do Iron filings stick to wires?
We now know that a wire with a current running through it will create a circular magnetic field.
This can be demonstrated by placing iron filings on a card with a wire running through its centre. When a direct current is passed through the wire the iron filings align to show the magnetic field.
The magnetic field can be shown to be in a circular pattern. When nearby iron filings get magnetised there is a magnetic attraction from one to another as they line up with the north pole of one adjacent to the south pole of its neighbour.
But do they stick to the wire?
Iron filings are ferromagnetic (having a high susceptibility to magnetism) and align themselves with the magnetic field. However, the wire is a non-magnetic metal (usually copper) and thus is not susceptible to magnetism and doesn't display any magnetic properties.
Therefore the answer is NO: iron filings will NOT stick to the wire.