Students want to build a simple motor to demonstrate the relationship between magnetism and electricity. Each student group has a wooden block, paper clips, a battery, and some copper wire. What additional material is necessary to build a
simple motor?
A An iron nail is necessary to produce a temporary magnetic field.
B. A magnet is necessary to produce a permanent magnetic field.
C. An iron nail is necessary to act as the electrical circuit load.
D. A magnet is necessary to act as the electrical circuit load.