Iron filings around a current carrying coil on OHP to show field.

Iron filings around a current carrying coil on OHP to show field. Closing a switch on the 6V battery sends a current (4 amps) through a coil of copper wire (about 20 turns), creating a magnetic field that resembles that of a short bar magnet. The coil runs through a glass plate. Medium-coarse iron filings are sprinkled onto the glass near the wire. The filings form field line patterns which are visible when projected on a screen. NOTE: The coil can burn up if the power is left on too long. A Timer Box is attached to the battery to notify you to turn off the power.