$[$Chemical Engineering$]$ A cylindrical container with a drain pipe sticking out of the bottom is filled with water. The drain hole is covered initially. After the water is added, the hole is uncovered and water allowed to flow out through the pipe. A ruler is positioned on the clear container so that the water height can be measured. A timer is used to determine how long it takes for $1$ cm of water to leave, all the way until all the water is gone. If the pipe length and diameter, and tank$/$water height and diameter are known, how can the viscosity be determined?