Tin foil hat validity, as the effect of strong radio waves has been documented for quite some time. A well-constructed aluminum foil enclosure would approximate a Faraday cage for parts of the body enclosed by metal, reducing the amount of radio frequency electromagnetic radiation passing through to the parts of the body covered by the foil. Unlike a foil hat, a Faraday cage is a complete enclosure. A foil hat does not protect the face, and other uncovered areas of the body are not protected. A common high school physics demonstration involves placing an AM radio on aluminum foil, and then covering the
Tin Woodman iron or steel but coated with tin (in order to prevent rusting) is called a "Tin" object, as a "tin bath", a "tin toy", or a "tin can"; thus, the Tin Woodman might be interpreted (in English, at least) as being made of steel with a tin veneer. One passage in "The Road to Oz," by Baum himself, wherein the Woodman attends Ozma's birthday party accompanied by a Winkie band playing a song called "There's No Plate Like Tin," strongly implies that this is the case. Another explanation may be that the Woodman is "chiefly" made of tin, with iron