Differences

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--- demonstrations:3_oscillations_and_waves:sound_waves:beat_notes:start [2019/03/25 18:07] – demoroom
+++ demonstrations:3_oscillations_and_waves:sound_waves:beat_notes:start [2020/03/06 18:57] (current) – demoroom
@@ Line 1: / Line 1: @@
 ====== Beat Notes ======
-{{tag> interference acoustics oscillations_and_waves frequency unlocated}}
+{{tag> interference acoustics oscillations_and_waves frequency located}}
 <WRAP box right>
@@ Line 17: / Line 17: @@
 ===== Purpose =====
-Demonstration of the constructive and destructive interference ('beating') observed when two nearly identical frequencies are played together.
+Demonstration of the constructive and destructive interference ('beating') observed when two nearly identical frequencies are played together. [[https://en.wikipedia.org/wiki/Beat_(acoustics)|Relevant Wikipedia page]]
 ===== Apparatus =====
   * Pair of tuning forks
+  * (Optional: Vernier Labpro, Microphone, and computer with LoggerPro)
 // Or alternatively://
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 ===== Setup =====
-  * Two organ pipes, one with a variable frequency adjustment are sounded together. By moving the frequency adjustment of one pipe to obtain a frequency close to the other pipe will result with beats.
+  * Place the pair of tuning forks with resonance boxes on a table so that the open ends of the boxes face the audience. Now, strike both of the forks with a rubber mallet. If the adjustable fork is damped so that it's frequency is slightly different than the other, beats will be heard.
+  * If you are using a LabPro, attach it to the microphone sensor and a computer with LoggerPro open. Set data collection for a few seconds and display the graph of the beating frequencies
-  * Two identical tuning forks on resonance boxes should be placed on the demonstration bench so that the open ends of the boxes are angled to face the audience. If one fork is now damped slightly with a damping piece attached to it, beats will be heard.
+  * If you do this with a pair of organ pipes, you will need an assistant. Get your assistant to sound the non-adjustable pipe continuously, and begin sounding the adjustable pipe yourself. Adjust the pipes so that they are sounding nearly the same note, and beats should be heard.
 ===== Notes =====
+The frequency of the 'beats' tone that you hear is equal to the difference between the two other frequencies being played. If the frequencies are sufficiently close, you may not hear any beats at all, and if they're too far apart the beats will have a high enough frequency to be heard as a [[wp>combination tone]].
+The basic principle is an extension of superposition.
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 </WRAP>
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-| **Location** | ---- |
+| **Location** | T4 |
 | **Maker** | Unknown |
 | **Current State** | Working |