Movie 1 shows positive rheotaxis of spermatozoa in the stream of fluid. After few secons, the pump was turned off and the spermatozoa started to swim in random directions. Chamber height is 127 um.Spermatozoon's lenght 55um.
Picture A shows vertical cross section through the chamber
Picture B - how the chamber works
Picture C - dead spermatozoa in the stream
Picture D - spermatozoon's trace
Nice article how small organisms swim at low Reynolds's number