Coriolis density meters, also known as mass flow meters or inertial flow meters, work on the principle of vibration to measure phase shifts in the vibration of a bent thin walled tube. The bent thin walled tube is rotated around a central axis. When there is no mass in the bent section, the tube remains untwisted. However, when the density inside the bent section increases, the inbound flow portion of the bent pipe drags behind the out flow portion. This twisting causes phase shifts which result in changes in the resonant frequency of the thin walled tube. Therefore, the resonant frequency is directly affected by the density. Higher density media causes a larger coriolis effect if the volumetric flow rate is constant. Flowing media causes a frequency and a phase shift of the bent pipe, which are proportional to the mass flow rate of the sample.