Automated vs. Manual: Investigation of Human Error Associated with Time-related Measurements

Abstract

In this study, we have studied the human error associated with time-related measurements. The free fall of an object is one of the most significant time-related phenomena studied in physics. This study compares manual time measurements using a stopwatch with analyzed time derived from a recorded video of the free fall of a small ball to evaluate the precision of human timing during the experiment. In this experiment, a small ball was dropped from a height of one meter. The free fall experiment was repeated three times by four participants, resulting in a total of twelve trials using a smartphone stopwatch. The time analyzed from the video was considered the reference value for the experiment. Video analysis was performed using an image processing method implemented in Python. The average time measured using the stopwatch was (0.40 ± 0.01) seconds, while the free fall time obtained from the video was 0.4667 seconds. Relative to the reference value, the results from the stopwatch showed a percentage error of 14.2918%. For this phenomenon, the value of time calculated using the equation of motion was 0.4516 seconds. Compared to this value, the result from the video showed an error percentage of 3.3437%. The time measured using the stopwatch was examined to evaluate the accuracy and consistency of human measurements. Contributing factors to human reaction time errors include variability in participant's eye levels, the reaction time when starting and stopping the stopwatch, and difficulty stopping the stopwatch precisely when the ball hit the ground. Environmental air resistance further affected time deviations. This experiment provides insight into the unpredictability introduced by human error in manual timing techniques during physics investigations. The results highlight the need for precise instruments to improve reliability and accuracy in experimental physics.