 Another property of water that we will go through is cohesion and adhesion, which are the basis for phenomena such as surface tension and capillary action. We are going to first talk about what surface tension and capillary action are, and then we will talk about what cohesion and adhesion are. So surface tension can be easily observed by putting an object onto water, a water surface and watching it float, if the object is too heavy it shrinks. So you can say that surface tension is the property of the surface of a liquid that allows it to resist an external force. What about capillary action? Remember when you spilled water on your shirt? The water didn't just stay in one spot, it moves and spreads around through very narrow routes created by the fibers. Capillary action especially is one of the most foundational mechanisms of life, is how plants draw water up from the roots, is how our body delivers nutrients throughout each individual cell. It is also responsible for the rising dam and building materials. You can say that capillary action is the ability of a liquid to flow in narrow spaces without the assistance of or even in opposition to external forces like gravity. Otherwise, plants would not be able to draw water up from the roots, or our body would not be able to deliver nutrients from our intestines to our brain. Surface tension and capillary action is based on the same forces and attractive force. When two like molecules are attracted to each other, we call this cohesion. And on the other hand, when two like molecules are attracted to each other, we call this adhesion.