Every day, millions of people pass through walk-through metal detectors at airports, schools, concert venues, courthouses, ...

In a metal like copper, however, the outer electrons swim around freely and are shared by all the atoms. That’s why ...

So, you've binged a few treasure-hunting shows and now you're wondering if your own old detector in the garage can find you a pirate chest. One of the first questions that may pop up in your head ...