PURPOSE: To illustrate a combination of simultaneous orthogonal oscillations.
DESCRIPTION: Stroke the notches with the V-shaped section on the stroker stick. The end pin will execute circular or elliptical motion, causing the propeller to rotate. Rubbing either your thumb or your forefinger on the stic k (by sliding your hand slightly back and forth) reverses the phase of the horizontal oscillation with respect to the vertical oscillation of the pin, causing the rotation of the pin and the propeller to reverse.
SUGGESTIONS: Practice. With a bit of luck, you can actually use this device to answer questions, predict the future, etc.
REFERENCES: (PIRA unavailable.) See Demonstration Reference File for a number of articles related to this device. These gizzits may also be called the "Gee-Haw Whimmy Diddle," the HOOEY stick, or the Notched Stick with Rotor. "
EQUIPMENT: Ouija windmill, as photographed.
SETUP TIME: None.
Go back to Lecture-Demonstration Home Page.