What determines if a metal will set off a metal detector?

Question

i kno not all metal will my jewelery didnt last year at the airport or when i went htrough at the courthouse but there was that lady who's nipple ring set it off did she just have cheap jewelery does it have to do with its magnetism (i think thats the right word) or anything like that? i only use surgical stainless steel anyway

Answer 1

problably its magnetic proporties. most metel detectors are diffrent.(it went off because of a s***w in my leg one time) this coud also relate to a stored electical chearge in some thing

Answer 2

It's hard to tell, I usually go through just fine with all my jewelry on(minus watch). But every now and then it's set off by the lanyard I wear my I.D. on. I wouldn't wear much and just be prepared to remove it if you need to.

To give you some idea, I usually wear small earrings, a ring, my lanyard has a little bit of metal on it and my wings(which are a metal pin).

Answer 3

I think it has more to do with the density of the metal than its magnetism, but I'm not really sure.  And of course how big the metal thing is.

Also, different airports have their scanners set to different sensitivity levels (which just seems stupid to me).  For a while I was flying the same route regularly, and my shoes would always set it off going from A->B but they never would set it off going from B->A.  This was before you had to take your shoes off, btw.