A small, often forgotten, but significant advantage of digital cameras is that they can be fed through countless airport X-ray machines and the pictures feel no ill effects. Try that with a film camera (or even the bag of film you plan to use on your vacation) and things quickly start to get cloudy. Literally.
That's because X-rays expose film just like light does, although the X-rays don't get blocked by the camera body quite so well as the visible spectrum does. This is the trick that PopSci's Theodore Gray used to make a DIY X-ray camera.
In fact, you don't even need a camera to try this. Take a sensitive piece of film -- Gray used ISO 3000 Fuji instant film -- and wrap it in something that will keep the light out (do this in the dark, of course), like tinfoil.
Next, Gray put and old butterfly-shaped earring on top of the package, and hung a radium button (saved from an old science kit) above that. After a day and a half, he developed the film in a Polaroid machine and there on the sheet was a photogram of the butterfly.
Amazingly, you don't even need the radium button. Although glowing, radioactive watch hands would be even quicker, if you are patient (as in, several months patient), you can use ordinary sodium-free salt to beam particles from decaying potassium-40 at the film.
You could actually try this at the airport, packing up your wrapped film and trinket together in an envelope, say, and letting it run through the X-ray machine. Just be prepared to do some fast talking. And don't tell them I sent you.
Gray Matter: DIY X-Ray Photos [PopSci. Thanks, Alexis!]
Photo: Mike Walker/PopSci
