Why do instruments go out of tune?

Answer: Temperature changes string tension

Temperature changes string tension ✓ — Correct! String instruments go out of tune as temperature and humidity cause wood to expand/contract and strings to stretch. Wind instruments change pitch with temperature affecting air density and metal expansion. Mechanical stress from playing also gradually changes tension and shape.

Sound waves wear down materials — Wrong. Sound waves don't wear materials. Instruments detune from physical changes—wood movement, string stretching, and temperature effects.

Age weakens the instrument — Wrong. Age can affect tuning stability, but the main causes are environmental factors (temperature, humidity) and mechanical stress.