MCAT Physical › Viscosity
Which of the following would tend to decrease the viscosity of a liquid flowing through a pipe?
Increasing the temperature
Increasing the pressure
Decreasing the diameter of the pipe
Decreasing the volumetric flow rate of the liquid
Increasing the length of the pipe
The factors that influence viscosity are:
1. The molecular structure of the given liquid (i.e. what liquid is flowing)
2. Temperature
3. Extreme pressure
Liquids become less viscous with increased temperature. As temperature increases, the molecules move faster relative to one another and spend less time in contact with each other. This behavior causes the intermolecular forces to decrease, so the viscosity decreases.