======Singing Crystal Glass======


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**Alternative titles:** Resonance of Wine Glasses
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====Summary====                   
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====Procedure====  
  - Choose one crystal wine glass and inspect it for chips or cracks.
  - Measure the total volume the glass can hold using a graduated cylinder or scale.
  - Dry the outside of the glass and place it on a stable, non-slip surface away from electronics.
  - Wet your fingertip with clean water and lightly rub along the rim to start the tone.
  - Once the tone is steady, observe and record the pitch using a tuner app or frequency analyzer.
  - Add a measured amount of water to the same glass, gently swirl to settle, and repeat the rub-and-measure step.
  - Continue with several added amounts, recording the pitch after each fill.
  - Compare how the pitch changes as the water level rises in the same glass and summarize the pattern you observe.



====Links==== 
Science at Home - SE1 - EP8: Physics of Sound - Part 1: Singing Wine Glass - The Sci Guys: 
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Resonating wine glasses - Keith Gibbs: 
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📄 Resonance in a Crystal Glass - Casey Riscoe, Hope Titus, Mary Bywater, Matthew Taylor: [[https://tuhsphysics.ttsd.k12.or.us/Research/IB11/RiscTituBywaTayl/index.htm]]\\


====Variations====
  * Test specific fractional fills of the same glass (such as eighths, quarters, halves) and compare the pitch at each level.
  * Repeat the sequence after gently warming or cooling the water to see if temperature changes affect the tone.
  * Replace water with a thicker liquid (for example, sugar solution) to examine how viscosity influences the sound.
  * Record with a microphone and visualize the waveform and spectrum to look for overtones and shifts in resonance.




====Safety Precautions====
  * Handle the crystal glass carefully; do not press hard on the rim to avoid cracking.
  * Keep liquids away from laptops, outlets, and power cords; use a splash-safe setup.
  * Clean up spills immediately to prevent slips and protect equipment.




====Questions to Consider====
  * Why does adding liquid to the glass tend to lower the pitch? (The added mass and fluid motion dampen the rim’s vibration, reducing the resonant frequency.)
  * What properties of crystal help it “sing” more clearly than ordinary glass? (Its composition and structure allow stronger, longer-lasting vibrations with less internal damping.)
  * How might glass thickness and rim shape influence the tone quality? (They change stiffness and damping, which alter both pitch and sustain.)
  * Why are additional tones sometimes heard besides the main pitch? (Overtones arise from different vibration modes of the rim and interactions with the liquid and air.)