Tin foil hat
hat
A tin foil hat is a hat made from one or more sheets of tin foil or aluminium foil, or a piece of conventional headgear lined with foil, often worn in the belief or hope that it shields the brain from threats such as electromagnetic fields, mind control, and mind reading. The notion of wearing homemade headgear for such protection has become a popular stereotype and byword for paranoia, persecutory delusions, and belief in pseudoscience and conspiracy theories.
"Tin foil" is a common misnomer for aluminium foil in English-speaking countries; packaging metal foil was formerly made out of tin before it was replaced with aluminium.
Origin
Some people – "Tin Foil Hatters" – have a belief that such hats prevent mind control by governments, spies, mobsters, corporations, extraterrestrial, or paranormal beings that employ ESP or the microwave auditory effect. People in many countries who believe they are "targeted individuals", subject to government, corporate, or criminal spying or harassment, have developed websites, conference calls, and support meetings to discuss their concerns, including the idea of protective headgear. Vice Magazine wrote that the tin foil hat in popular culture "can be traced back in a very weird and prescient short story written in 1927 by Julian Huxley" titled The Tissue-Culture King, wherein the main character uses a metal hat to prevent being mind controlled by the villain scientist. Over time the term tin foil hat has become associated with paranoia and conspiracy theories.
Scientific analysis
Effects of strong electromagnetic radiation on health have been documented for quite some time. The efficiency of a metal enclosure in blocking electromagnetic radiation depends on the thickness of the foil, as dictated by the "skin depth" of the conductor for a particular wave frequency range of the radiation. For half-millimetre-thick aluminum foil, radiation above about 20 kHz (i.e., including both AM and FM bands) would be partially blocked, although aluminum foil is not sold in this thickness, so numerous layers of foil would be required to achieve this effect.
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This entry incorporates text from “Tin foil hat” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.