Adhesion and Fracture Mechanism The Third Law

The Attractions of Gravity, Magnetism and Electricity reach to very sensible distances and so have been observed by vulgar Eyes, and there may be others which reach to so small distances 

We have seen in the previous chapters that adhesion phenomena can be explained generally by two fundamental laws the first is that all objects jump together as a result of universal atomic and molecular attractions the second is the effect of intervening contaminant atoms which reduce the molecular attraction, often causing jumping in steps as each contaminating molecular layer is squeezed out. 

The purpose of this chapter is to describe some of these adhesion mechanisms, especially starting with the Brownian and cracking mechanisms, then leading on to a whole range of subsidiary mechanisms which make adhesion 

PROBLEM OF THE WIDE RANGE OF ADHESION ENERGY VALUES 

To explain the wide adhesion variations shown in Fig. 7.1 we have to introduce some other mechanisms, giving us the third law of adhesion. Some of these are very obvious and have been mentioned earlier, for example, roughness 

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