To measure period , we are allowing the pendulum to complete five swings in order to reduce human reaction speed. Trial 5x period (s)/ period T (s) 6. 70 -uncertainty of average 6.76 5x period is sample 6 . 68 Standard deviation / V3 Average 6.7 + 0.02 1.34:0.004 which was calculated on excel 0.02 uncertainty of average of single period IS 0.02 /S = 0.004 Theoretical value forT : Im = 2 nJ - e = 32. 1 + 0. 2 9 : 9.80 + 0.07 where uncertainty in U ( TM ) = 2x J "dim . (ly + dim. (9)] 2 gravity was choosen based on local variation J [ spg . ull ) ] + Pas . u (g)]2 in local