A Simple Water Pressure ExperimentThis simple water pressure experiment shows the effect of pressure on the flow rate of water. This is useful for not just investigating water flow, but also for understanding the relationship between voltage and power in electric circuits. 
Materials NeededYou will need the following: * a 2 liter or bigger juice or milk container ProcedurePut three neat and same size holes in the drink container. One hole is at the bottom, one in the middle and one near the top. Fill the container with water, sit it in an elevated place (facing a sink, preferably!).
What is Happening?The three holes are at different depths. At the bottom hole there is a lot of water pushing down, so the water coming out at the bottom is under a lot more pressure than the other 2 holes. The middle hole has the next largest amount of pressure, while the top hole has the least amount of pressure. You can gauge the pressure by how far the water travels from the container, as seen in the second image. When I asked my 9 year old daughter why the water went further from the bottom hole, she said "because the water there weighs more". Perhaps not the most precise scientific explanation, but the basic idea is there. NotesThe smaller the holes, the greater the rate of flow from the holes. Also, if you are using a plastic container you could heat the metal skewer to make perfectly round and even sized holes. This last tip is NOT recommended for unsupervised children! Why Is This A Solar Experiment?On the face of it, this has nothing to do with solar science. However, this experiment is an excellent analogy for the meaning of voltage in electrical circuits and its effect on the amount of energy produced. These are two important concepts for understanding how to maximize the effectiveness of solar arrays. Return from Water Pressure Experiment to Solar Energy Education or return to the Green Planet home page for more Solar Power Facts.
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