Sunday, August 05, 2018
Constants and variables 101, Biblegraph edition
Still listening to episodes of Blackstone Magic Detective at bedtime. Each episode is a very short adventure followed by instructions for a parlor trick you can do at home. This episode has a 'lie detector' trick. While the magician isn't looking, pick up a coin in one hand and hold it to your forehead for a moment. Then be sure that both hands are gripping the same way, and place both fists down on the table. How does the magician know which one has the coin? The hand that was up by the forehead is comparatively pale.
Trying the up-down with my own hands, it works easily in bright light. The difference is hard to see in typical 'living-room' light.
Makes me wonder. Was the trick inspired by the original polygraph? One hand up in the air, the other flat on the bible. The bible is just a distractor. The differential enables the watcher to eliminate the baseline. Deplorable hands were permanently dirty, so changes in blood pressure would be fairly hard to detect. But if one hand is up and the other is down, the down hand will be getting comparatively redder, and the arteries comparatively more prominent, when stress increases. This wouldn't work with the degenerate version of the oath (I do or I will) but a long session of questions would give enough time for a careful observer to spot the difference.
Labels: Constants and Variables, Metrology
¶ 1:01 AM
