|MadSci Network: Physics|
Water is a conductor, like a metal, just not a very good one. Therefore, just like in a conductor, the current (flow of electricity) takes the path of least resistance. Because you are asking about water, I'm assuming you are thinking of a large body of water, such as a swimming pool or lake. In a large conducting medium, there are many different "paths" for the electrical current to spread out over. For example, if an electrical source (such as a toaster) were dropped in the center of a circular swimming pool, the current would flow from the center outwards, uniformly in all directions. The density of the current would be highest near the source and decrease as a function of distance from the center (the radius). This problem is easy because of the symmetry of the swimming pool and because the electrical conductivity is uniform in all directions. These problems get more complex as the shapes get more complex (a kidney-shaped swimming pool) and elements enter the system which change the uniformity of the properties (a floating pool sweeper with a metallic hose). Maxwell's equations (complex partial differential equations) are used to solve this type of problem, but the math gets very ugly very quickly. A good, basic description can be found in a physics text book such as Sears, Zemansky, and Young, or Halliday and Resnick, in the chapters which discuss electricity and magnetism. Chris Seaman Alcoa Technical Center
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