Which instrument is a classic friction idiophone?

• A. Glass Harmonica
• B. Musical Saw
• C. Gong
• D. Triangle

Answer: (B)

Friction idiophones produce sound from the vibration of their own solid body when friction is used, not by striking or blowing air through them. The musical saw fits this idea because the tone comes from rubbing or bowing along the edge of the flexible blade; the friction makes the blade vibrate and sustain a pitch, giving a characteristic eerie, violin-like glissando. This continuous vibration via friction is what marks it as a friction idiophone, and it’s a well-known, classic example of how rubbing a solid body can create musical sound.

The gong and triangle are driven by striking, which makes them struck idiophones, not friction instruments. The glass harmonica produces sound from vibrating glass touched by fingers, which is also friction-based, but the musical saw is the more iconic example typically highlighted as a classic friction idiophone.