Is Silver Magnetic?
Silver isn’t noticeably magnetic. In fact, only iron, nickel, cobalt, gadolinium, neodymium and samarium are magnetic in our everyday lives. Knowing that silver isn’t magnetic is useful since it can help you spot fake silver. For example, if someone is trying to sell silver jewelry or coins it’s not a bad idea to test them with a magnet. If they are attracted to the magnet they aren’t pure silver (note the clasp on the end of a silver chain is often magnetic so you can ignore this part).
If silver isn’t magnetic, how do metal detectors find it?
Metal detectors are able to find non-magnetic metals, like gold or silver, using a principle called the Lenz effect. Moving the metal detector over a gold coin will set up a slight electric field in the coin. The metal detector can sense this field and alert you to the coin.
You can see the effect in the video below. An ingot of pure silver isn’t attracted to a magnet. But when the magnet is passed over the silver it causes the ingot to move.
Video of Silver Interacting with a Neodynium Magnet
What’s happening is that the moving magnet sets up an electric current in the silver ingot. The electric current has its own magnetic field It is this magnetic field that is interacting with the moving magnet. So while silver isn’t magnetic it can interact with magnets if they are moving.
If you had a silver pipe you could drop the magnet down the pipe and it would fall very slowly. This also works with aluminum and copper.
When a magnet moves by some metals (like aluminum, copper, lead …) it causes small electrical currents to form (called eddy currents). Any electrical current will produce a magnetic field. As the magnet falls it generates eddy currents in the metal. The falling magnet then interacts with the magnetic field produced by the eddy currents. That’s why the magnet falls so slow.
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