How do the piano, harpsichord, celesta, and organ produce sound in different ways?

Although these instruments share a keyboard interface, they produce sound through distinct mechanical and physical processes:

• Piano: This instrument functions as both a stringed and percussion instrument. When a key is pressed, a felt-covered hammer strikes a string, causing it to vibrate.12
• Harpsichord: Unlike the piano, the harpsichord produces sound through a plucking mechanism. When a key is depressed, a jack lifts a plectrum (made of quill, plastic, or leather) that plucks the string.13
• Celesta: This is a metallophone that uses a simplified piano action. When the player presses a key, small felt hammers strike tuned metal bars, which are resonated by wooden chambers to reinforce the sound.14
• Organ: Pipe organs are aerophones that produce sound by directing pressurized air through pipes. The air column is set into motion either through flue pipes (similar to woodwinds) or by vibrating brass reeds actuated by the airflow.56