Changing the Beat Frequency

Moving the clamp lower on the arm of the tuning fork reduces the beat frequency.

Discussion

Two resonance boxes and tuning forks, both at 440 Hz, are closely positioned. A small clamp is attached near the top of one arm of the second tuning fork. The effect of this additional mass is to lower the frequency of this tuning fork. When both forks are struck, beat tones can be heard. Next, the clamp is lowered. At this position on the tuning fork arm, the tuning fork frequency is higher than it was with the clamp nearer the top of the arm, so is closer to the 440 Hz frequency of the second tuning fork. Both forks are again struck and lower frequency beats can be heard.