Velocities and accelerations are measured and visualized in silicon microchannels using particle tracking velocimetry (PTV). Both pulsatile and stationary flows are generated in channels with different geometry. Distinct differences between flow regimes and geometries are shown. Flow separation occurred at Re = 84 for the channel with an expanded bifurcation shown by streamlines from long exposed images. Moving least squares are used to find the ensemble-averaged positions of the measured velocities from tracking. This is needed to find the local and convective accelerations.