Time sequence in video playback?

[FlyingSide]

I'm doing a physics project involving timing the time it takes for 40 dominoes to fall depending on a dependent factor. I'm filming it with a webcam hooked up to my laptop, but they all fall in a relatively small amount of time [like 1.1s, 1.2s, etc.]. Whenever I play the video back in Realplayer, it only displays the elapsed time in hours, minutes, and seconds. Is there any way I could have a video playback that would give me small increments of time? I really need help!

Thanks!