Next place the compass on top of the wire, align the wire and needle, and again
close the switch. Make another sketch showing the wire, the compass (include the
direction it is pointing), and the direction of current flow. Also indicate the direction the
compass points when the switch is open.

8. How is the direction of the field above the wire related to the direction of the field
   beneath the wire?

9. Formulate a rule for the direction of the field around a current-carrying wire based
   on your observations. You may find it useful to hold the wire and move the
   compass around the wire. Hint: Start by pointing the thumb of your right hand in
   the direction of current flow and relate the field direction to your fingers.

10. Predict the shape of the field if you were to coil thewire into a loop. Will the
    rule you developed still work? (If not, you may need to adapt your rule.)
    Record your prediction in your report file.

To investigate the shape and direction of
magnetic fields due to coils of wire, first connect
the following circuit: (Be sure to use the smaller
coil with many turns.)

Place the coil on a sheet of paper (this is
to catch any iron filings that miss our
target). Now place this coil between the
two small boxes and place the cardboard
over the coil so the cardboard rests on the
boxes.

Sprinkle iron filings on the cardboard and close the switch. Tap the cardboard so
the filings arrange themselves and display the field shape clearly. Add more filings if
necessary.

11. Sketch the magnetic field shape in your notes. Describe the shape in your report file.

Again, use a compass to indicate the direction of the magnetic field in and around
the coil. Add the appropriate direction arrows to your sketch.

12. Compare the direction of the field lines to the direction of the current.

13. Compare the magnetic field shape and direction from the coil to the magnetic field
    for a bar magnet. Discuss similarities and differences.

Submit your work file and ask for the next set of instructions, HO-14B