Water on ice; influence on friction

The dynamic friction between polyethylene and a mixture of crushed ice and small amounts of a very dilute solution of H₂SO₄ in water was measured at temperature from 0 degrees C to -20 degrees C. The liquid has only a moderate 'lubricating' effect which indicates that the generally low friction between polyethylene and ice and snow cannot be explained simply by a liquid or liquid-like layer on the ice. Larger amounts of liquid (>or=1%) lead to an increase in friction, due probably to viscous drag. Contrary to what is commonly stated, the increase in friction, which is observed as the temperature approaches 0 degrees C, is not caused by viscous drag.