Tuning Fork on Bench

A vibrating tuning fork produces a faint sound when held in the air. When placed on a solid bench, the sound becomes much louder because the vibrations are transferred to the bench, which acts as a resonator and amplifies the sound.

1. Strike a tuning fork gently against a rubber stopper or soft surface to make it vibrate.
2. Hold the vibrating tuning fork in the air and have students listen to its faint sound.
3. Press the base of the vibrating tuning fork onto a wooden bench or tabletop.
4. Ask students to compare the sound level before and after contact with the bench.
5. Explain how the bench amplifies the sound through resonance and forced vibration.

• Try placing the tuning fork on different surfaces (wood, metal, plastic, hollow box) to compare sound amplification.
• Place the tuning fork against a hollow object (such as an empty box or container) for even greater amplification.
• Test tuning forks of different frequencies to explore how pitch interacts with resonance.
• Compare a speaker producing sound, with placing it on a solid bench.

• Strike the tuning fork against a rubber pad, not hard objects, to avoid damage.

• Why does the tuning fork sound louder on the bench than in the air?
• What role does resonance play in this demonstration?
• How is this similar to the way musical instruments amplify sound?
• What kind of surfaces produced the loudest sound, and why?