Tin foil hat Tin foil hat A tin foil hat is a hat made from one or more sheets of aluminium foil, or a piece of conventional headgear lined with foil, 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. Note that "tin foil" is a common misnomer for aluminium foil; packaging metal foil was formerly made out of tin before it was
Bruce foil foil far out from the centerline of the hull, and angling it so that a perpendicular line through the center of the underwater portion of the foil will intersect the center of pressure of the sails. Like a traditional centerboard, the Bruce foil is generally a symmetric design, such as the NACA 00xx series, which relies on the leeward slip of the hull to provide the angle of attack needed to generate lift. When mounted on the lee side, the Bruce foil generates an upwards lift in addition to lateral force, and when mounted on the windward side, it generates