References

1. Waves produced by striking the end of a thin rod are not simple longitudinal waves (sound waves). Longitudinal waves only occur in large volumes of material. In thin rods, the rod surface also moves in the radial direction as a wave passes. For example, in the case of aluminum the sound velocity is 6420 m/s in bulk material, while the velocity of similar waves in thin rods is 5000 m/s. first citation in article
   
2. R. C. Nicklin, "Measuring the velocity of sound in a metal rod," Am. J. Phys. 41, 734 (May 1973). [ISI] first citation in article
   
3. Michael T. Frank and Edward Kluk, "Velocity of sound in solids," Phys. Teach. 29, 246–251 (April 1991). first citation in article
   
4. Oakes Ames, "A direct measurement of the speed of sound in rods," Am. J. Phys. 38, 1151–1152 (Sept. 1970). [ISI] first citation in article
   
5. Nobuo Naba, "Observation of longitudinal vibration of metal rods," Am. J. Phys. 40, 1339–1340 (Sept. 1972). [ISI] first citation in article
   
6. David Potter, "The speed of sound in an iron rod," Phys. Teach. 40, 56–57 (Jan. 2002). first citation in article
   
7. For the 0.95-cm diameter aluminum rod, I used a 3/8-in diameter 1/16-in thick NdFeB magnet. Magnets were obtained from Force Field, 2606 W. Vine Drive, Fort Collins, CO 80521; 877-944-6247. They typically have small quantities of magnets other than the 40 or so for sale at their website at http://www.wondermagnet.com. first citation in article
   
8. The LabPro interface with Logger Pro software from Vernier Software was used to collect data in this experiment, 13979 SW Millikan Way, Beaverton, OR 97005-2886; 503-277-2299; http://www.vernier.com. first citation in article
   
9. CRC Handbook of Chemistry and Physics (CRC Press Boca Raton, FL, 1985), p. E-43. first citation in article