Abstract: Starting from the established condition of Stokes＇ law, we discuss the correction term of Stokes equaton. The Reynolds number correction term relative error on the viscous drag effects is studied and the falling ball diameter, sticky lag coefficient on Reynolds number effects are also analyzed. It is concluded that the measurement error is controlled within the allowable error range, it must satisfy the five established conditions of Stokes＇ law in the experiments.

Key words: Stokes law, coefficient of viscous, failing ball method, Reynolds number, modification factor