Tin foil hat "Signs" and "". 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
Foil (fencing) or fastening a knob on the point ("blossom", French "fleuret"). In addition to practising, some fencers took away the protection and used the sharp foil for duels. German students took up that practice in academic fencing and developed the "Pariser" ("Parisian") thrusting small sword for the "Stoßmensur" ("thrusting mensur"). The target area for modern foil is said to come from a time when fencing was practised with limited safety equipment. Another factor in the target area is that foil rules are derived from a period when dueling to the death was the norm. Hence, the favoured target area is the