A student from Sidney, Australia compares the distance he obtained from the 1-st spark mark to the 20-th spark mark, with the similar result of a student who did the experiment in Gaithersburg, Maryland. Both students operated identical setups powered with 60 Hz AC, reported no missing spark marks, and certified precision of their measurements in four significant figures. What difference in the results was found? Data for the gravity acceleration constant are provided in the text. Acceleration in Gaithersberg is 9.810424 + or - 0.000008 m/sec2 Acceleration in Sydney is 9.7967134 + or - .0000019 m/sec2