Tin foil hat 43803 224939325 2008-07-11T02:36:51Z 72.81.93.5 Removed external link to commerical site--it contibutes nothing to the topic. [[Image:ManWearingTinFoilHat.jpg|thumb|A man wearing a tin foil hat.]] A '''tin foil hat''' is a piece of [[headgear]] made from one or more sheets of [[tin foil]], [[aluminium foil]] or similar material. People wear the hats in the belief that they act to shield the [[brain]] from such influences as [[electromagnetic field]]s, or against alien interference, [[mind control]] and [[mind reading]]. The idea of wearing a tin foil hat for protection from such threats has become a popular [[stereotype]] and term of derision. The phrase serves as a [[byword]] for [[paranoia]] and is often used to characterize [[Conspiracy theory|conspiracy theorists]]. == Tin foil hats and paranoia == Various web sites claim that people believe in the efficacy of tin foil hats and similar devices to stop the voices in their head or prevent the government, paranormal beings, or aliens from reading and/or controlling their mind. These people believe that the foil deflects mind control signals from, for instance, project [[HAARP]], which allegedly transmits mind-control signals from mobile phone towers. These draw on the stereotypical images of mind control operating by [[Extra-sensory perception|ESP]] or by technological means, like [[microwave auditory effect|microwave radiation]]. Belief in the effectiveness of tin foil hats is popularly linked to mental illnesses such as paranoid [[schizophrenia]].<ref>{{ cite web | title = Hey Crazy--Get a New Hat | url = http://www.bostonist.com/archives/2005/11/15/hey_crazyget_a_new_hat.php | accessdate = 2007-04-05 | date = [[15 November]] [[2005]] | publisher = Bostonist }}</ref> == Scientific basis == [[Image:TinFoilHat002.jpg|thumb|Two people wearing tin foil hats.]] The belief that a tin foil hat can significantly reduce the intensity of incident radio frequency (RF) radiation on the wearer's brain is not completely without a basis in scientific fact. A well constructed tin foil enclosure would approximate a [[Faraday cage]], reducing the amount of [[Radio waves|radiofrequency electromagnetic radiation]] entering from outside. A common high school physics demonstration involves placing an AM radio on tin foil, and then covering the radio with a metal bucket. This leads to a noticeable reduction in signal strength. The efficiency of such an enclosure in blocking such radiation depends on the thickness of the tin foil, as dictated by the [[skin effect|skin depth]], the distance the radiation can propagate in a particular non-ideal [[electrical conductor|conductor]]. For half-millimeter-thick tin foil, radiation above about 20 kHz (i.e., including both [[AM band|AM]] and [[FM band]]s) would be partially blocked.<ref>{{ cite book | title = Classical Electrodynamics | first = John David | last = Jackson | publisher = Wiley Press | year = 1998 }}</ref> The effectiveness of the tin foil hat as [[electromagnetic shielding]] for stopping radio waves is greatly reduced by the fact that it is not a complete enclosure. Placing an AM radio under a metal bucket without a conductive layer underneath demonstrates the relative ineffectiveness of such a setup. Because the effect of an ungrounded Faraday cage is to partially reflect the incident radiation, a radio wave that is incident on the inner surface of the hat (i.e., coming from underneath the hat-wearer) would be reflected and partially 'focused' towards the user's brain. While tin foil hats may have originated in some understanding of the Faraday cage effect, the use of such a hat to attenuate radio waves belongs properly to the realm of [[pseudoscience]]. A study by [[graduate student]]s at [[MIT]] determined that a tin foil hat could either amplify or attenuate incoming radiation depending on frequency. The effect was observed to be roughly independent of the relative placement of the wearer and radiation source.<ref>{{ cite web | url = http://people.csail.mit.edu/rahimi/helmet/ | title = On the Effectiveness of Aluminium Foil Helmets | subtitle = An Empirical Study | first = Ali | last = Rahimi | coauthors = Ben Recht, Jason Taylor, Noah Vawter | accessdate = 2007-04-05 | date = [[17 February]] [[2005]] | publisher = Ali Rahimi }}</ref> At GHz wavelengths, the [[skin depth]] is less than the thickness of even the thinnest foil. Despite some allegations that [[electromagnetic radiation]] (EMR) exposure has harmful effects on health ,<ref>{{cite web| url = http://news.independent.co.uk/environment/article362557.ece| title = Story on EMR radiation and health in ''The Independent.''}}</ref> at this time, no link has been verifiably proven between the radio-frequency EMR that tin foil hats are meant to protect against and subsequent ill health.<ref>{{cite web| url = http://www.osha.gov/SLTC/radiofrequencyradiation/healtheffects.html|title = Occupational Safety and Health Administration page on Radio Frequency Emissions and Health}}</ref> == Tin foil hats in popular culture == <!-- A few *significant* examples is sufficient here, folks. --> * ''[[Eastenders]]'' character [[Joe Wicks]] was briefly portrayed constructing and wearing his own tin foil hat as part of a storyline which saw him suffering from [[schizophrenia]]. * The novel ''[[Idiots in the Machine]]'' by Edward Savio portrays a character who believes that tin foil keeps harmful gamma rays away and becomes a media sensation, marketing a successful line of foil hats to Chicago. * In an episode of ''[[The Simpsons]]'', "[[Brother's Little Helper]]", Bart becomes paranoid after taking an ADD drug called Focusin, leading him to believe that [[Major League Baseball]] is spying on him and begins donning a tin foil hat. At the end of the episode, Bart turns out to be right when he shoots an MLB satellite out of the sky. * The tin foil hat was an [[April Fool's Day]] item for the [[MMORPG]] ''[[World of Warcraft]]'', created by [[Blizzard Entertainment|Blizzard]] to parody player paranoia about their character information being searchable on the World of Warcraft armory website.<ref>{{ cite web | title = Introducing the Tinfoil Hat | url = http://www.worldofwarcraft.com/info/items/tinfoilhat.xml }}</ref> * In [[M. Night Shyamalan]]'s 2002 film ''[[Signs (film)|Signs]]'', the Hesses don tin foil hats to protect from invading aliens. * One character in the 2007 film ''[[The Signal (film)|The Signal]]'' wears a tin foil hat in an attempt to block the titular "signal" turning people into murderous madmen. == References == {{Reflist|2}} == External links == * [http://gizmodo.com/5022355/crowd+controlling-medusa-ray-gun-puts-voices-inside-your-head Crowd-Controlling MEDUSA Ray Gun Puts Voices Inside Your Head] * [http://www.straightdope.com/columns/000609.html Do tinfoil helmets provide adequate protection against mind control rays?] &ndash; from [[The Straight Dope]] * [http://zapatopi.net/afdb.html Aluminium Foil Deflector Beanie] &ndash; parody say some, original scientific research by Lyle Zapato, say others * [http://www.paladin-press.com/detail.aspx?ID=28 Aluminum Foil Deflector Beanie: Practical Mind Control Protection for Paranoids] &ndash; book by Lyle Zapato * [http://eclectech.co.uk/mindcontrol.php Tinfoil Hat Mind Control Musical Animation] &ndash; parody * [http://www.theregister.co.uk/2005/11/11/tinfoil_hats_as_government_plot/ Tinfoil hats attract mind-control signals, boffins learn] * [http://people.csail.mit.edu/rahimi/helmet/ "On the Effectiveness of Aluminium Foil Helmets: An Empirical Study"] &ndash; performed at [[MIT]] [[Category:Paranoia]] [[Category:Hats]] [[Category:Mind control]] [[Category:Pseudoscience]] [[fi:Foliohattu]] [[sv:Foliehatt]]