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
FOIL method FOIL method In elementary algebra, FOIL is a mnemonic for the standard method of multiplying two binomials—hence the method may be referred to as the FOIL method. The word "FOIL" is an acronym for the four terms of the product: The general form is: Note that is both a "first" term and an "outer" term; is both a "last" and "inner" term, and so forth. The order of the four terms in the sum is not important, and need not match the order of the letters in the word FOIL. The FOIL method is a special case of a more