The friction of a sliding tactile contact was measured in an apparatus which simulated a keyboard. Results were taken for several materials. The friction coefficient was found to decrease with increasing load and with increasing speed. Experiments at varying humidity and surface roughness helped to define the friction mechanisms. It is concluded that tactile friction is predominantly adhesive, but modified by liquid bridging between the ridges of the skin and the counterface. Increased bridging due to higher humidity causes increased friction from viscous shearing effects, while increased roughness allows fewer bridges to form, decreasing the friction.

A study of the mechanics of ice friction was performed in which various theoretical models were compared to experimental results. Analytical models indicate that ice friction is affected by load, speed, ambient temperature, and thermal properties of the counterface material. All four parameters were varied and the results compared to analytical models with additional study using regression analysis. Conclusions indicate that under some conditions the friction of ice is subject to a thermal control mechanism.

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