Annex B - Additional Research Data

First, water molecules (two atoms of hydrogen and one atom of oxygen joined together) naturally stick to one another, so they clump together in big droplets on the window. The forces that make them do this are called cohesive forces (and the process involved is called cohesion). Second, the water droplets also stick to the glass without any help or glue. Different forces are at work here known as adhesive forces (the sticking process is called adhesion). Now the cohesive forces must be bigger than the adhesive forces or the water wouldn't form droplets at all. Instead, it would just spread out in a very thin layer on the glass—much as oil does when you spread it on water. But the adhesive forces are still pretty strong: some of the water droplets that stick to your window are surprisingly big. (W. C. (2015, September 23). Adhesives (glues). Retrieved March 04, 2016, from

All adhesives are based on polymer structures, but the intermolecular mechanisms underlying specific bond strengths depend on the nature and preparation of the bonded materials as well as the application environment. Bonds are subject to tensile, compressive and shear stresses to which individual adhesives respond in different ways. (Brampton, F. (2014, March 05). Factors that Affect Adhesive Success. Retrieved March 07, 2016, from

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