3D40.31 - Driven Chladni Plates
Drive a plate at a given frequency and elegant patterns will form.
Obtain the Pasco Mechanical Vibrator, the Driven Chladni Plate Assembly, Sugar, IR light, B+W Camera, Plastic Bin to capture sugar runoff, Function Generator, Momentary Contact Switch, and Cables. Once the listed items are gathered, ensure the Pasco vibrator is in correct orientation in the driven plate assembly and that it is in the locked state. Attach banana cables to the Pasco vibrator and connect the opposing ends to the function generator. Choose a geometric plate to use and secure it into the Pasco vibrator. Set up the IR light to illuminate the geometric plate. Arrange the B+W camera in a overhead viewing angle. Unlock the Pasco vibrator and set the outputs on the function generator to a low voltage and one of the resonant frequencies provided here or on the accompanying sheet for the chosen geometric plate.
**Contact instructor to see which geometric shapes they plan to use and provide a single mechanical vibrator for each plate requested**
Sprinkle generous amounts of sugar evenly on to the plate, set the amplitude to midrange, close the momentary switch then carefully adjust the frequency knob until there is a noticeable movement of the sugar on the plate. The movement will be highly local so only places here and there will show antinodal movement. The sugar will pile up in the nodal areas and display a complicated geometric pattern. Many fine and subtle patterns are available if you have the patience and recognize the small disturbances made when passing rapidly through a resonance, then using the fine adjustment and once the peak is found increasing the amplitude.To change plates, lift the entire mechanical vibrator assembly out of the box and replace with a different vibrator/plate combination
**The geometric plates are attached to a pasco mechanical vibrator via banana plug connectors. It is best to start at a low frequency and slowly increase. Lower frequencies tend to overdrive the plate so the amplitude control must be used continuosly to maintain a maximum drive without overdriving.**
Guitar/Volin: 80, 133, 167, 285, 387, 460, 555,602, 640, 685, 844, 1009 Hz
Square: 70/71 (degenerate mode), 77-79, 186, 200, 359, 492, 815, 950 Hz
Circle: 151, 505, 579, 979, 1203, 1384 Hz( plus many more between these)