Practical it is not, but this gadget sure is nifty! The Hydro Power Calculator ($9.95) is powered by water - all you have to do is fill the "batteries" with tap water and you're ready to calculate.
Water-powered battery consists of two electrodes made of special alloys, which, when immersed in water, produce electricity through a chemical reaction.
Simply refill the battery as the water evaporates - typically every 2 to 3 months. The battery has a minimum continuous life of 2 years.
Fun and educational - From the NeatoShop: Link | More fun Back To School Items
Now this would have been a sweet Mystery Sale item! Any chance of bringing those back?
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Umm, water is merely the electrolyte, the anode will collect ions from the cathode and eventually the product will stop working due to corrosion. So it is not powered by water but rather by the metals used as electrodes.
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