How does the frequency of vibration of a tuning fork change when additional mass is added to the tines of the fork?

When additional mass is added to the tines of a tuning fork, the frequency of vibration decreases. This is because the added mass lowers the natural frequency of the fork, as the system becomes heavier and thus requires more energy to vibrate at the same rate. According to the principles of physics, the frequency is inversely related to the square root of the mass; therefore, increasing mass results in a lower frequency.