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Metal detector use electromagnetic induction principle, using a alternating current through the coil, resulting in a rapidly changing magnetic field. The magnetic field can be induced in the metal object within the eddy currents. Eddy currents will produce magnetic field, the magnetic field affect the original upside down, triggering an audible warning signal detector.
Important role in the archaeological
Metal detectors can detect not only the arms, but also to detect coins, keys and other metal objects.
Archeology in the field, most exhibits are metals, such as firearms warheads, cartridges, bullets, artillery and shells, shrapnel and / or the sword and so on, specifically the battle took place which exhibits depends on the historical period. Therefore, the field archaeologists, the most important tool is a simple metal detector.
For decades, as has been rightly considered a "weapon", a metal detector has been plagued by criticism. Until 1983, Richard. Fox and, later, Douglas. Scott (Douglas Scott) through the analysis of small Bighorn battlefield proved through a systematic metal detector survey, archaeological decades of hard work can be in a very short period of time be completed within. According to their estimates, the metal detector workers excavated in a small Bighorn battlefield, 5,000 pieces of ancient artifacts in the traditional approach might only find one of the 10 or so.
Today, skilled workers with the archaeologists and metal detectors are a heritage conservation work, archaeological field play an important role in protection of cultural relics are responsible for accurately recording the location of found objects, and a "packaging, labeling, and to tag. " In other words, each piece of ancient artifacts have been packaged together, labeled and put it out when digging the holes drilled in order to be removed before the study is to identify it for later precise location and mapping of .
Metal detectors are increasingly being used to assist the surface-penetrating radar (SPR, Surface Penetrating Radar), and other ground-penetrating radar system. Initially by the United Kingdom (Britain) developed for detecting plastic landmines, SPR system can locate the surface 30 meters below the exception object. The system also offers a range of clues to help identify the user does not yet dug up the evidence.
But even find the location of the metal artifacts, it is only half the battle. Sometimes, metal artifacts left half of the original look. The mid-90s in the Battle of Monmouth (Battle of Monmouth) analysis of the process, U.S. archaeologists found a number of surface mottled muskets warheads have been held down as thin as the chewing gum. In order to determine the original size, a Mingjiao Dan. Sivilich (Dan Sivilich), engineers, archaeologists came the invention of a formula, this formula combines physics and chemistry will be used to calculate any non-spherical musket The original bullet diameter. It (well-deserved) has been called the "Sivilich formula" (Sivilich Formula), now in the archaeological field everywhere in the world every day use.
Once the deformed or incomplete guns or shells head out of the original size has been estimated, ballistics experts will be joined to begin calculating the range of artillery fire. Many people - professions - like
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