======Musical Bottles======


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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:** Blowing Bottles for Sound
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====Summary====                   
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====Procedure====  
  - Collect three narrow-neck bottles and clean them.
  - Try blowing across the top of each bottle to produce a resonant sound.
  - Measure one bottle’s height and mark halfway up the side; fill it with water to that mark.
  - On another bottle, mark three-quarters of the way up and fill with water to that level.
  - Leave the third bottle empty.
  - Blow across the empty bottle and note the pitch.
  - Blow across the half-full bottle and compare the pitch to the empty one.
  - Blow across the three-quarters full bottle and compare the pitch to the others.
  - Observe how the pitch changes as the air volume decreases.



====Links==== 
Science Minute: Explaining sound and vibrations with bottles - 9NEWS: 
{{youtube>YdAZQhIABAM?}}\\

Why Blowing in Bottles Makes Sound and Helmholtz Resonance - RimstarOrg: 
{{youtube>PZVeJ2rh6ts?}}\\

📄 Musical Bottles - Science Buddies: [[https://www.sciencebuddies.org/stem-activities/musical-bottles]]\\


====Variations====
  * Use bottles of different shapes or sizes to test how shape affects pitch.
  * Slowly fill a bottle with water and record how the note changes at each stage.
  * Compare bottle sounds to a piano or tuner to identify the musical notes.
  * Instead of blowing, tap bottles with a mallet to observe sound changes.



====Safety Precautions====
  * Handle glass bottles carefully to avoid breakage and cuts.
  * If using a mallet, tap gently to prevent breaking the bottles.



====Questions to Consider====
  * Why does the empty bottle make the lowest pitch? (Because it has the largest volume of air, resulting in the lowest frequency.)
  * What happens to the pitch when more water is added? (The pitch increases as the air volume decreases.)
  * How does the bottle’s shape or neck size affect the sound? (Wider openings or shorter necks generally produce higher frequencies.)
  * Can you match the notes from the bottles to a musical scale? (Yes, depending on the bottle size and water level, you can approximate musical notes.)