This may seem like a silly question, so I shall offer my apologies in advance. I wish design an empirical experiment to show time. I should be able to use a stopwatch to obtain a time value, say 1 s. In order to show that the value which I have measured is not due to (my) bias, I must also devise a control. Using my heart rate (about 60 pulses/min = about 1 pulse/s) could I show that the stopwatch has actually measured about 1 s of time? - or would I have used the stopwatch to measure the approximate rate of my heart? - or conversely, used my heart as a clock to approximately measure a 1 s count of the stopwatch? Confusing! Can anybody suggest an experimental method allowing for an objective and empirical measure of time?