I was reading about RFID's and Richard Stallman's incident with the UN, and now I am curious as to whether or not aluminum foil can actually block radio frequencies. If it cannot, how about tin? If we wanted to be absolutely certain no one was reading an RFID tag, unless we wanted them to, we could make a lead-sheathed wallet of sorts, but this would be a little cumbersome.

So is lead actually any better at stoping radio waves than any other metal? I really dont see why it could be, but it seems to be a pretty darn common belief.

 

Well I googled this, and I assume you read it on slashdot. As far as I know, you could make an effective faraday cage out of aluminum foil. Meaning a conductive mesh or surface with no openings; such a thing blocks em waves of certain frequencies (notice the square mesh on microwave doors, its a metal mesh, keeps you from being mircowaved).

 

I of course could be wrong, but I think aluminum should work fine, like most metals would.

'']So is lead actually any better at stoping radio waves than any other metal? I really dont see why it could be, but it seems to be a pretty darn common belief.

Lead is better at blocking radiation than other metals because it is denser. Next time you get an X-ray, ask what the jacket they give you is made from, its lead. Also, if you go around the back of a hospital you can usually pick up lead containers they use to ship radioisotopes to hospitals (at least they do at my hospital). The lead is about 2 inches thick, and it shields a tiny amount of material, like smaller than a film canister.