Final answer:
The sustaining pedal on a piano lifts the dampers off the strings, allowing for sustained notes and richer resonance. This pedal facilitates sympathetic vibrations among strings, enriching the overall sound and increasing the instrument's ability to resonate with external frequencies.
Step-by-step explanation:
The sustaining pedal on the piano, also known as the damper pedal, has a very important role in the instrument's sound. When the pedal is pressed, the dampers that normally mute the strings are lifted, allowing the strings to vibrate freely. This creates a richer, more resonant sound, as the strings can continue to vibrate even after a key is released. The resonance created by the sustaining pedal adds depth and volume to the piano's sound and can even cause strings to resonate in sympathy with others, a phenomenon known as sympathetic resonance.
For example, if you sing a note while pressing the sustaining pedal, the piano strings that are tuned to the same frequency as your voice will start to vibrate, creating sound even though they were not directly played. This illustrates how the piano can resonate in response to external sound waves, and this effect is particularly noted when playing at the natural frequency of the strings. The concept is similar to the way a paddle ball tied to an elastic band will bounce with increasing amplitude when its base is moved at its own natural frequency, which demonstrates the idea of resonance.