Sound's loudness or volume is directly determined by the amplitude of its sound waves.
The Relationship: Amplitude and Loudness
According to the provided reference, the amplitude of a sound wave determines its loudness or volume. This is a fundamental relationship in the study of acoustics and wave physics. It establishes a direct link between a physical property of the wave (amplitude) and a perceptual quality of the sound (loudness).
Here's a breakdown of this relationship:
- Larger Amplitude: A sound wave with a larger amplitude corresponds to a louder sound. Think of pushing a swing higher; its amplitude of motion increases, just as a louder sound wave has greater displacement from its resting position.
- Smaller Amplitude: Conversely, a sound wave with a smaller amplitude corresponds to a softer sound. Pushing the swing gently results in smaller amplitude swings and a "softer" motion.
This relationship can be simply summarized:
| Amplitude | Loudness |
|---|---|
| Larger | Louder |
| Smaller | Softer |
What Sets Amplitude?
The amplitude of a sound wave is set by the vibration of its source. When an object vibrates, it displaces the surrounding air particles. The extent of this displacement determines the amplitude of the sound wave created. For example, striking a drum harder causes the drumhead to vibrate with a larger amplitude, producing a louder sound wave than striking it softly.
Illustrative Example
The reference mentions an example comparing sounds C and B in Figure 10.2, stating that sound C is louder than sound B. While we don't have the figure, this type of example typically shows that the wave representing sound C has a larger amplitude than the wave representing sound B, visually demonstrating the principle that greater amplitude equates to greater loudness.
In summary, the dependence of sound on the amplitude of its waves is precise: amplitude is the direct determinant of loudness or volume, with larger amplitudes producing louder sounds and smaller amplitudes producing softer sounds.
