Traveling on airplanes is routine for millions of people. When people check in at airports,
their luggage and carry-on bags have to go through an elaborate screening process.
The machines that perform this duty are typically metal detectors or X-ray scanners.
The principle of a metal detecter is quite simple. Inside the machine are wire coils.
This current creates an electromagnetic field. The dilection of the current flow is reversed
several thousand times every second. This current or pulse slows down and disperses.
Any metalic object like keys,coins,a knife or even a cell phone which happens to enter this
electromagnetic field will influence the speed of the current. When a passenger puts their
bags through an x-ray machine, they go through a type of electromagnetic energy. In an airport,
x-ray technology is used in CT scanners. The x-rays bounce off the objects inside the suitcase,
measuring the dinsty and mass of each object. Incidentally i dislike a metak detecter and ct scan.
Since this is not that effective, newer high-tech systems have been developed that are capable
of detecting chemical components in individual items.