Blowing across the tops of bottles with varying water levels produces musical notes of different pitches. The pitch depends on the amount of air inside the bottle, with less air producing higher frequencies.

1. Collect three narrow-neck bottles and clean them.
2. Try blowing across the top of each bottle to produce a resonant sound.
3. Measure one bottle’s height and mark halfway up the side; fill it with water to that mark.
4. On another bottle, mark three-quarters of the way up and fill with water to that level.
5. Leave the third bottle empty.
6. Blow across the empty bottle and note the pitch.
7. Blow across the half-full bottle and compare the pitch to the empty one.
8. Blow across the three-quarters full bottle and compare the pitch to the others.
9. Observe how the pitch changes as the air volume decreases.

Science Minute: Explaining sound and vibrations with bottles - 9NEWS:

Why Blowing in Bottles Makes Sound and Helmholtz Resonance - RimstarOrg:

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

• 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.

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

• 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.)