The Mystery of Changing Pitch When Stirring Powdered Drink Mix into Water
Have you ever noticed how the pitch of the spoon clinking against the glass seems to change while stirring? This intriguing phenomenon can be explained by the properties of sound waves and the behavior of substances when mixed with water. In this article, we will explore why the pitch changes as powdered drink mix is added to a glass of water, and delve into the underlying physics behind this interesting observation.
Understanding the Experiment
The experiment described in the original text involves stirring water in different containers and adding powdered drink mix to observe the change in pitch. By using two wine glasses and a beer bottle, we can better understand how the volume of liquid and the presence of bubbles affect the sound produced when stirring.
Why Does the Pitch Change?
Initially, it was thought that the pitch increased as bubbles rose to the surface, given that a more compressible fluid would result in a lower resonant note. However, the experiments conducted showed that the pitch actually decreased as the glass became heavier due to increased liquid volume, making it more difficult for the glass to vibrate and produce sound.
Olde-time Wine Glass Pitches
The author mentions an old television show where performers would create music by rubbing their fingers around the top of wine glasses filled with varying amounts of water. These glasses required considerable tuning due to the changes in volume and thus pitch. The experiments with wine glasses confirmed the same principle. As the volume increased, the pitch decreased.
Beer Bottle Blues
Interestingly, when experimenting with a beer bottle, the author noticed a different pattern. Initially, filling the bottle with water and blowing across the top produced a lower tone. However, as more water was added, the pitch of the sound increased. This is because the air column trapped inside the bottle becomes shorter, resulting in a higher pitch sound.
Exploring the Physics
The change in pitch can be explained by understanding the resonance and vibration of the glass. When the liquid level increases, the glass becomes more massive and resistant to vibration, leading to a lower resonant frequency. Conversely, when the air column in an open container (like a beer bottle) decreases, the frequency of the sound waves increases, resulting in a higher pitch.
Conclusion
While this experiment might not require a deep knowledge of physics, it highlights the fascinating interplay between sound, liquid volume, and the properties of the containers they sit in. The observations made are not just fun and interesting, but they can also provide insights into sound psychology and the impact of physical properties on our sensory experiences.