Atypical two-tine tuning fork is barely audible when held vibrating at an arm's length. It is enough, however, to touch its base to a table or, better, to a resonance box and the emitted sound becomes much louder. An inquiring student may pose questions: Why is a bare tuning fork such a weak emitter of sound? ; What is the role of the resonance box? ; Where does energy connected with larger intensity of emitted acoustic waves come from?