Metal detectors are useful pieces of equipment used by archaeologists. The distance into the earth’s surface that they can penetrate limits many metal detectors. They are not usually necessary if the area being surveyed has already been surveyed by a magnetometer, as they too would detect the presence of any metal located beneath the surface.

The metal detectors send impulses down into the ground, and when they hit a metal object, they bounce back up and activate a bleeper to alert the operator of hidden metal.

The use of metal detectors by amateur archaeologists has in the past proven to be very useful in the discovery of sites possessing a wealth of archaeological artefacts. Once alerted to the presence of metal beneath the soil, professional archaeologists can use some of the site location techniques to determine the relevance of the finds, and where appropriate conduct excavations, which can often lead to the discovery of great archaeology. All too often though, metal detectors can give positive readings when the metal prompting such readings are simply old cans or other man made waste.