A reader pointed out yet another "water powered clock" to me, and asked:
What do you think? Scam, right? To me it sounds like it's got a battery in it, and water is just a conductor for it. "2 year lifespan" makes me even more certain...
Yes, that's kind of the deal.
Herein, I shall shamelessly reprint and slightly expand something I previously wrote as a comment on Book Of Joe:
Man, I'm tired of things like this. "Fruit Powered Clock", "Water Powered Radio", "Potato Powered Web Server" (that one required rather a lot of potatoes, as I recall). Some of them are complete hoaxes, but the commercial ones all do actually work. Every single one of them is misnamed, though.
In all of these cases, the object or liquid in between the electrodes is not "powering" anything. It is acting as the electrolyte, like the goo inside a flashlight battery or the acid inside your car battery. The actual power comes from an electrochemical reaction between the electrodes. For little gadgets like this one, the electrodes are generally paddles of copper and zinc.
All the electrolyte does is transport ions from one electrode to the other (and collect contamination along the way, which is why you mustn't eat the orange that's been "powering" that clock for the last couple of days). The actual power comes from the electrochemical difference between the material from which the electrodes are made. One electrode will be slowly eaten away, and the other will slowly crust up with crud.
To say otherwise - as the packaging for these devices invariably does - is like saying that your television is "powered by wire".
Science toys that're dumbed down until they're lying to us are an own goal.
29 May 2009 at 4:44 am
To be fair, the linked "water powered clock" does in fact include an accurate, though lightweight, description of how it works, which follows:
"The patented technology simulates a basic battery concept where two electrodes consisting of specially formulated alloys, one positive the other negative, are immersed in water. As soon as water comes in contact with both electrodes an electrochemical reaction takes place resulting in the production of electrical energy."
I'm not sure why they feel the need to mention it's patented or even how they managed to get a patent for what is essentially the same technology as every wet-cell ever made, but hey, at least they explain that it's not the water doing the work.
29 May 2009 at 5:37 pm
So, it simulates it, instead of doing it for real? I love little science toys.:)