VISCOSITY OF WATER AT VARIOUS TEMPERATURES

The relative viscosity of water has been measured with high precision in the range from 8 to 70° using a modified Cannon-Ubbelohde suspended-meniscus, dilution viscometer with a semiautomatic, optical viscometer reader. Measurements were made at 1° intervals with a relative precision of about 0.001%. The apparent energy of activation for viscous flow of water was calculated from these data. The result is given by an equation of the form ΔE‡ = A + BT + CT2 + DT3 + ET4. The root-mean-square deviation from this expression was 3.7 cal/g-mol (i.e., approximately 0.1% in ΔE‡). The results obtained did not reveal any abrupt changes, at discrete temperatures, in the observed energy of activation values. The suggestion is offered that some of the thermal anomalies (kinks") which have been reported in bulk properties of water may have arisen from structural transitions in ordered water structures near interfaces."