Which instrument is widely cited as a friction idiophone?

• A. Glass Harmonica
• B. Gong
• C. Triangle
• D. Cimbalom

Answer: (A)

The main idea is sound produced by friction on the instrument’s own material. A friction idiophone creates tones because the player's fingers rub against a solid surface, setting it into vibration without striking it. The glass harmonica fits this perfectly: damp fingers glide around the rims of glass bowls, and the rubbing action keeps the glass vibrating, producing a continuous, smooth tone. The pitch depends on the size and thickness of the glasses, so the instrument is classed as a friction idiophone.

In contrast, the gong and triangle produce sound by striking a metal surface, an impact mechanism. The cimbalom is a string instrument (a type of chordophone) whose sound comes from vibrating strings, not from friction of a solid body. That’s why they don’t fit the friction idiophone category.