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
Bruce foil a downwards force. Bruce foils can be mounted in pairs, one on each side, as used in some trimaran designs. In this case, the leeward foil works in conjunction with the leeward ama to provide lift, and the windward foil can be retracted to reduce drag. At equilibrium, the force from the foil and the sail will always be balanced, so capsize should be impossible, but in practice that is not the case. Since the foil's force is relative to the hull's movement through the water, and the sail's force is relative to the wind moving past the sail, sudden