A simple and low cost set-up for surface tension measurement of highly viscous liquids

摘要

A simple and low-cost set up has been described for measurement of surface tension of highly viscous liquids by drop-weight method.The set up has been described in literature for normal liquids.Data in terms of V/R~3 and corresponding factor F are given in literature for normal liquids.An equation has been developed between V/R~3 versus a factor F by polynomial regression using EXCEL-2000 spreadsheet software in Window-98.Here V is volume of drop of liquid passing through a tube of radius R.The tube of 3 min internal diameter has been used and this diameter has been measured by a vernier caliper.The setup has been applied to glycerol and the results are accurate within +-2.5% of literature values obtained by this simple setup.Further this apparatus has been used in determination of viscosity of commercial highly viscous unknown liquids.The results are reproducible.This simple apparatus can be used in Physical Chemistry practicals,with the help of the cubic equation found from EXCEL-2000 software.