What is a Metal Detector

A metal detector works something like sonar.
The base of the wand-like apparatus of the A metal detector contains a coil that emits an electromagnetic field into the ground.
Metallic objects, such as coins or rings, respond to this electromagnetic field by emitting their own fields.
The coil detects this and transmits this signal to the control box at the top of the wand. The result is a signal-usually a series of beeps letting the person operating the metal detector know that something has been found.
Obviously. unwanted objects, such as nails or random pieces of steel, are detected as well.