Ceramic knives cannot be detected by metal detectors because they are made of a non-metallic material. Metal detectors work by generating a magnetic field and then detecting any disturbances in that field caused by the presence of a metallic object. Since ceramic knives are not magnetic, they do not create any disturbances in the magnetic field and therefore cannot be detected by a metal detector.
This can be both an advantage and a disadvantage. On one hand, it means that ceramic knives can be carried through metal detectors without setting them off, which can be useful in certain situations such as airport security checkpoints. On the other hand, it also means that ceramic knives can potentially be used as a concealed weapon in places where metal detectors are used to screen for weapons.
It’s important to note that while ceramic knives are not detectable by metal detectors, they are still subject to other forms of screening and security measures. For example, airport security may use X-ray machines or other imaging technologies to detect ceramic knives or other non-metallic weapons.