Is it bedtime?

OMEGA touch pads and starting blocks are part of an integrated timing system capable of recording times to the nearest 1/1000th of a second. However, because it is not possible to build swimming pools in which each lane is guaranteed to be precisely the same length, Olympic and World Records are still recorded to the nearest 1/100th of a second.

A look at how the time-recording pads placed in the Olympic pool work.

Also, frame by frame of Phelps’ finish.

(via)