Water is one of the most important parts of the success of life on earth. The fact that water is polar gives it properties that a lot of other liquids don't have. One of these properties is cohesion, it is the ability of water molecules to hydrogen bond to each other. It allows water to stick together and be tugged through plant xylem via negative pressure. The cohesion in water gives it a tensile strength that rivals other substances that are much more solid. In addition to cohesion, water molecules are also good at adhesion. Adhesion is the property of water that allows it to bond to other polar surfaces. Adhesion is the reason that water can "walk" up a thin capillary tube. The ability to move up a tube also has to do with the surface tension of the water. As water climbs up the walls of the glass tube, the surface area of the water increases. The force of surface tension wants to decrease the surface area of the water, so it tugs the water up in order to maintain a more stable surface area. All of these forces play a role in moving water up a tube, however they are all stopped eventually by gravity.
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