======Bullroarer from String and Ruler======


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**Materials: **{{$demo.materials_description}}\\
**Difficulty: **{{$demo.difficulty_description}}\\
**Safety: **{{$demo.safety_description}}\\
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**Categories:** {{$demo.categories}}
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**Alternative titles:** Homemade Bullroarer
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====Summary====                   
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====Procedure====  
  - Tie one end of a length of string (about 1 meter) securely to one end of a flat ruler.  
  - Hold the other end of the string firmly in your hand.  
  - Stand in an open space away from people or fragile objects.  
  - Swing the ruler in a large vertical or horizontal circle.  
  - Listen to the deep humming or roaring sound produced as the ruler spins.  
  - Experiment by swinging faster or slower to change the pitch and volume.



====Links==== 
Making a Bullroarer out of a Ruler - Professor Chill: 
{{youtube>jLUkuYMH13M?}}\\


📄 Bullroarer - Wikipedia: [[https://en.wikipedia.org/wiki/Bullroarer]]\\


====Variations====
  * Try using different lengths of string to hear how the sound changes.  
  * Replace the ruler with different flat objects (paint stirrer, cardboard strip, or wooden slat).  
  * Decorate the bullroarer for use in science shows or demonstrations.



====Safety Precautions====
  * Use only in open spaces to avoid hitting people, pets, or breakable objects.  
  * Ensure the string is tied securely so the ruler does not fly off.




====Questions to Consider====
  * What causes the roaring sound of the bullroarer? (Air rushing past the ruler causes vibrations that create sound waves.)  
  * How does swinging speed affect the pitch and volume of the sound? (Faster spinning increases pitch and loudness.)  
  * Why does the flat shape of the ruler work better than a round stick? (A flat surface disturbs more air, producing stronger vibrations and sound.)  
  * Where in history or culture have bullroarers been used? (They have been used in traditional ceremonies and communication by many cultures worldwide.)