“Laminar” fountains have become quite popular due to the desirable aesthetics that result from a smooth shaped fluid held together with its own surface tension during flight. Check out videos of “laminar fountain” on the web. To convert turbulent to laminar flow a conduit is often transitioned to a large diameter, and then subdivided into many smaller ones, sometimes called straighteners. Calculate the Reynolds number for a pipe that is originally 25 mm in diameter and carrying 8 m 3 /h of 20°C water. That flow is then directed to a 75 mm pipe and stuffed with plastic drinking straws, each with a diameter of 3 mm. Did the flow change from turbulent in the small pipe to laminar in the larger subdivided pipe?