Electromagnetically Spinning Sphere Viscometer

We have developed a simple system for viscosity measurement in the range of 10-3 to 101 Pa·s. An aluminum sphere revolves in a sample cell under a rotating external magnetic field, and the rotational speed of the sphere gives the sample viscosity. Low viscosities can be measured by using a micro-probe sphere, since the viscous torque applied to the sphere overcomes the frictional force at a sufficiently small sphere radius. The system is free from contamination and can be easily applied to medical and biological studies.