The Viscosity of Glycerin Based on Stokes’s Law and the Landau-Lifshitz Equation Tested with the Underdamped Hamonic Oscillation Experiment

Abstract

This research aimed to study the viscosity between the Landau-Lifshitz equation model and Stokes' law by underdamped harmonic oscillation. The data of the steel ball's movement is collected and processed by tracker program to find the resistance coefficient () and the angular velocity of the vibration (). Comparison of viscosity values ​​​​​from viscosity meter. The results showed that and the viscosity value increased with the concentration of glycerin, but the value decreased. The viscosity values ​​from the Landau-Leifsitz equation are close to the values ​​obtained from the instrument. The Stokes' law can be used to describe the viscosity values ​​while constant velocity, unlike the Landau-Leifsitz model equations which consider the effect of objects at non-constant velocity. When studying the relationship between the value of  and viscosity, it was found that the tendency increased with the length of spring extension. At the stretch distance of 2 cm, there was less in-plane oscillation. Hence, the viscosity at the stretch distance of 2 cm close to the measured instrument, but at 70% glycerin concentration, the value was more than 70% different from the measured instrument. However, at 70% glycerin concentration, the value is more than 70% different from the measurement device. One of the reasons is that at high concentrations, some of the glycerin is attached to the object's surface. Therefore, it was concluded that the stretch distance of 2 cm and the concentration of 10%, 30%, and 50%, the experimental viscosity ​​was consistent with the measuring instruments which are suitable for developing classroom teaching.