Where does the energy come from in a canal lock?


by amalgamma
Tags: canal, energy, lock
mfb
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Apr5-12, 08:43 AM
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Some energy could be gained from tides, if the canal would be flat (or had a connection at sea level). But the panama canal is long, the height difference is not very large and the canal is not at sea level at the moment. You could try to get some energy from the locks, as water from rivers flows down there. But I doubt that this would give you much power.
haruspex
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Apr7-12, 07:52 AM
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It might help if you imagine that at first that boat is anchored fast to the riverbed. When the water flows in from upstream it floods over the (watertight) boat. Now release the boat and see the weight of descending water supplying the energy to lift the rising boat.
sophiecentaur
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Apr7-12, 12:24 PM
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Quote Quote by amalgamma View Post
I'm still a bit baffled by the seeming effortlessness of the process. Therer are many unintuitive phenomena in nature, and I guess I'll have to accept this as one more. I never could get my head around potential energy, anyway---it always seemed like giving a name to the inscrutable, treating energy as a substance like an alchemist or something.
There is loads of (solar) energy involved in evaporating a volume of water that is equivalent to the weight of the boat. OK, it's "free" energy but the Nuclear reactions in the Sun produce 1kW on every square metre of the Earth's surface (at the Equator). If you imagine that weight of water falling (as rain) into a large bucket on one side of a huge see-saw, then the boat would also be lifted up. That would be "effortless" too and you could raise the boat up to the height of the raincloud, too.

You are quite justified in feeling uneasy about Potential Energy as a commodity. Energy is not an easy concept, even though it's something very familiar that our lives revolve around. It was a smart move when Scientists made the connection between all the various forms of energy. Joule did very well to put the mockers on the old 'Caloric' theory of heat.


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