ENVS 2060 Lecture Notes - Lecture 6: Chemical Polarity, Water Content, Capillary Action
26 Jul 2020
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Document Summary
Water is made of 2 hydrogen atoms and one oxygen atom. Hydrogen atoms not equally spaced around oxygen = polar molecule (one side positively charged the other negative) Dipolar character: allows water to form hydrogen bonds with other water molecules and with polar functional groups on surface of clay/organic matter. Water molecules attracted to ions in solution. Cohesion: used to describe attraction between water molecules. Adhesion (aka adsorption): attraction between water molecules and surfaces. Adhesion and cohesion combine to allow soil particles to retain water and control of its movement. Capillary rise: interaction of polar water molecules with surfaces/other water molecules. Height depends on size on individual pores and related to diameter of the pore. Example: glass tube with small diameter placed in water, water will move up into the tube. Reflects reaction of attraction of water to glass surface (adhesion) and attraction of one water molecule to another (cohesion)
