3. Screw Or Unscrew A Screw
In order to take something apart it's usually necessary to unscrew a screw . For us mere mortals we select either a flat or a Phillips screwdriver . Unscrewing some of those screws can be nasty business if they are stuck or stripped. The primary unscrewing function is to turn a tiny piece of metal around in a circle. In 1968 that would have seemed next to impossible with the sonic screwdriver. This nascent use of the screwdriver was used once in season 5 in Fury of the Deep to remove the screw from a pipe leading from the ocean. The screwdriver returned in season 6 for six more appearances screwing and unscrewing yet more screws . The second Doctor has screwed or unscrewed more screws than any other Doctor. But just how would the screwdriver remove a screw? Scientists at Engineering and Physical Sciences Research Council (EPSRC) have been able to convert sound to obtain a flow of magnetism known as spin current. By use of a piezoelectric element the spin current turns a piece of metal. This science takes directional sound waves and produces torque and would be the key to turning a Screw. If you don't believe me, click on this link and see The Real Sonic Screwdriver; http://youtu.be/K2DfEhjipLE