Why can a piano play both soft and loud sounds more easily than a harpsichord?

The piano is capable of playing both soft and loud sounds more easily than a harpsichord because of its fundamental mechanical design. While a harpsichord produces sound by plucking its strings with a plectrum, the piano uses a system of felt-covered hammers that strike the strings.12

The harpsichord’s plucking mechanism is incapable of significant dynamic gradation; because the plectrum always plucks the string with the same force regardless of how hard the key is pressed, the player cannot produce sustained crescendos or varied volume through finger pressure alone. To change volume, harpsichordists must rely on mechanical shifts, such as engaging different sets of strings or registers.234

In contrast, the piano—originally named gravicembalo col piano e forte ("harpsichord with soft and loud")—was invented by Bartolomeo Cristofori specifically to solve this limitation. The piano's action utilizes an intermediate lever that provides a velocity advantage, allowing the hammer to strike the string with varying force based on the player's touch. This mechanism, combined with an escapement that allows the hammer to rebound quickly, enables the performer to control the volume of each note dynamically.56