Greek_Geek Posted September 20, 2011 Share Posted September 20, 2011 I don't believe in PMM's, but I'm trying to understand the physics of why the capillary and water mill PMM doesn't work. Can someone explain it to me in terms of "energy". Here was my explanation: Nature is always trying to achieve the lowest state of energy. If water overcomes gravity due to capillary action, that means that the intermolecular bonding of water to the glass surface (coupled with surface tension) achieves a lower state of energy than gravity alone. That being said, why would the water suddenly succumb to the force of gravity after the siphon? Capillary action is the lowest state of energy for that system, so succumbing to gravity later would actually mean returning to a higher state of energy. Link to comment Share on other sites More sharing options...
swansont Posted September 20, 2011 Share Posted September 20, 2011 The end point in a siphon system is significantly lower than the starting point. That decreases the energy. With capillary action, it just needs to be lower than the highest point the capillary action can reach to have lower energy. Link to comment Share on other sites More sharing options...
CaptainPanic Posted September 20, 2011 Share Posted September 20, 2011 Water goes up in a capillary, but it's actually attracted to the surface. To separate the water from that particular surface takes energy (the same as the difference in height of the waterin the capillary and its original level + efficiency losses). In other words, if your capillary sucks water up, the water will never form droplets that fall off at a higher level. It will only form droplets at a level lower than the original water level. The only way to get the water out is to force it out somehow by using energy to get it out (for example, you can squeeze it out). Link to comment Share on other sites More sharing options...
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