We explored the hydodynamic instability of a viscous fluid on a rotating cylinder. Our power law model described the behavior at steady state of a the viscous fluid rotating at low speed on a cylinder. This phenomenon happens for example when you are scooping honey with a spoon. Honey flows down from the spoon and you can "catch" it by rotating the spoon. We then explored some instable behaviors of this hydrodynamic system at higher rotational speeds.