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PocketLab Voyager: Beat Phenomena with LED's and #50 Lamps

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Submitted by Rich on Fri, 08/18/2017 - 20:29

It is quite well known that when two frequencies of sound are close together, beats are produced and heard.  Demonstrations of this phenomenon are common in acoustical studies in physics classes.  In this lesson we investigate three laboratory techniques for seeing beats instead of hearing them.  These visual beats can be recorded and studied by the use of the PocketLab app and Voyager’s light sensor.  The first technique uses two #50 lamps that are driven at slightly different AC sine wave frequencies.  The second technique uses two LED's that fade in and out at two slightly different rates.  The third and final technique makes use of two LED's that are blinking on and off at different frequencies.

Beats produced by a pair of #50 bulbs
Grade Level