Hobbies And Interests
History
The origins of the modern metal detector trace back to the 19th century and the invention of the induction balance system by Heinrich Dove. These prototypes were much cruder, less effective, and typified by their enormous use of battery power. The modern metal detector was invented by Gerhard Fisher in the 1930s, who received the first patent for such a device.
Types
A metal detector can describe those large rectangular devices that check for guns at the airport or federal buildings as well as that handheld wand that helps people find dropped change and jewelry in the sand at the beach. Metal detectors are also utilized by the military to search for hidden land mines and during construction work to locate steel beams hidden behind concrete.
How it Works
A metal detector essentially works by producing an alternating current passing through a coil that produces an alternating magnetic field. When the detector is passed over metal, eddy currents are induced in the metal, producing its own alternating magnetic field. In this way the metal object is detected.
Security
It would not be until the 1960s that metal detection was used for non-military purposes. An increase in the incidence of airplane hijackings prompted the development of those airport screening devices that are now found in every airport in the world, as well as courthouses and federal offices.
Treasure Hunting
Many people buy inexpensive hand-held wand metal detectors to search for hidden treasure. What many people don't realize is that most of these metal detectors have a maximum detecting depth of one foot. In addition, there are some metals that are easier to find than others (iron is the easiest) and the actual size of the object plays a part as well (a tin can is easier to detect than a key.)
Warning
There has been some concern that people with pacemakers should avoid going through metal detector screeners. In fact, those with pacemakers need have no fear about walking through a metal detector at normal speed. While the metal of the pacemaker may set the detector off, it will not ham the pacemaker. However, it is not advisable to stand near one of these detectors too long, nor is it advisable to use a hand-held wand detector yourself.
Potential
Metal detectors have consistently gotten lighter and more sensitive over the decades and the potential for the detectors of the future looks bright. The impetus behind the latest technological advancements has been the necessity for increasing security as a result of the war on terror and the popularity of lone sociopaths looking to commit mass murder as a means toward suicide.