negative charge will adhere to water molecules to a greater degree. Glass has a negative charge but things like wax do not have this negative charge so you will see less of this phenomenon. Another interesting thing you will see related to cohesion is called capillary action. This is seen as the tendency of water to be more cohesive when in contact with another surface. In a capillary tube, you will see a rise in the water level at the edges and a sinking in the middle. If you have a thin enough tube, water will rise against gravity, which is what is known as capillary action. It works better with glass tubes because the glass is so negative in its own charge. This is also seen in the meniscus of water. The meniscus is the upper layer of a solvent in a narrow tube. With nonpolar solvents, you will see a flat meniscus because there is no adhesion to the sides of the tube. With water, though, you will see a concave meniscus, which is what you’ll see in figure 3:
Figure 3.
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