A meeting of two materials
Hugh R. Brown · Physics World · 1996
Objects made from polymeric materials, such as rubber and plastic, are incredibly useful. If we stop to consider what properties make these objects so vital for our everyday lives, the chances are that at least one involves the dynamics of interfaces. Take, for example, a computer mouse. It has a plastic case and contains a rubber coated ball, which rotates when the mouse is moved. The case is glued together such that the glue joints are sufficiently strong to withstand any rough treatment. The friction of the case on the desk must be small, but the friction of the ball on the desk must be high so that it rolls rather than slips when the mouse is moved.