Which of the following is a percussion Instrument?

Analyze the question: It asks which instrument is a percussion instrument. In the Sound/Musical Instruments topic of Physics, instruments are grouped by how they produce sound.

Explain the concept:

• Percussion instruments make sound when they are struck, hit, or shaken. Examples are drums, xylophone, gongs, cymbals and bells.
• String instruments produce sound from vibrating strings, which are plucked, strummed or bowed. Examples are the guitar and violin.
• Wind instruments produce sound from vibrating air columns, which are blown. Examples are the flute, trumpet and clarinet.

Solution, option by option:

• A. Flute: a wind instrument. Air is blown across the mouthpiece, so the air column vibrates.
• B. Guitar: a string instrument. Its strings are plucked or strummed.
• C. Piano: this one is tricky. Hammers strike the strings, but the sound comes from vibrating strings, so in physics it is usually classed as a string instrument. It is sometimes called a "percussion-string" hybrid, but it is not the best answer here.
• D. Trumpet: a brass wind instrument. The player's lips buzz into a mouthpiece, and the air column vibrates.
• E. Xylophone: a set of wooden (or metal) bars that are struck with mallets, and the bars themselves vibrate. This is a true percussion instrument.

Exam tip: Ask yourself what is vibrating and how it is set vibrating.

• Struck solid bars or skins mean percussion.
• Vibrating strings mean string.
• Vibrating air columns mean wind.

If an option such as the piano seems to fit two categories, choose the option that fits only one, which here is the xylophone.