Published on Sep 05, 2023
The objective: The objective is to test the hypothesis that greater liquid volumes and thicker liquids make a glass goblet resonate at a lower frequency. Also, to determine what effect size and/or shape of goblet has on frequency
I used a KORG Chromatic Tuner CA-30 to measure and record pitches of a small and big glass goblet filled at different volumes with either water, vegetable oil, or molasses. I repeated all trials.
I used the formula: f(2) = f(1)* 2^(x/1200), where f(2) represents the sound frequency in Hertz, f(1) the frequency of the closest semitone, and x the number of cents (a unit of pitch based on the equal tempered scale) away from the closest semitone, to convert the recorded pitches to frequencies.
Greater liquid volumes produce lower frequencies than goblets filled with less liquid. Oil produced higher frequencies than water, molasses lower than water, and the smaller goblet produced frequencies lower than the larger goblet. Results were very consistent and repeatable.
My hypothesis that as more liquid is added the frequency gets lower was correct. The size and/or shape of the glass also influenced the pitch along with the liquid's density. Liquid volume had a greater effect on frequency than liquid density, however.
This project was about how sound frequencies from glass goblets vary depending on the volume and type of liquid, and size and/or shape of the glass.