I saw this advert about a water powered digital clock. It claimed that “
the internal converter simply extracts electrons from water (or other liquid) molecules and provides a steady stream of electrical current acting as a fuel cell to generate power to the clock.”
Not that expansive so I got one out of curiosity.
After carefully adding in the water as directed. It took about a minute before the large LCD screen came to life. Programming the correct time and date is easy and honestly, I do like the large display. Based on the manual, a change of water is expected to be done once after every 5 to 7 weeks.
So, what is the scientific principle behind this clock?
The first thing is that the technology that they advertise does not exist -
a blatant lie!
The water is not the source of the power. The electricity is being produced by the difference in electrode potentials of the anode and the cathode which are inserted into the water. It’s just a battery, it looks a little bit different, but the clock draws a very small amount of current anyway. So its powered by a dissolving a hunk of zinc.
When the zinc is gone, the power is gone. But the clock draws so little power that it can run for years on that little bit of zinc. The water is just the medium for the electrons to move from anode to cathode.
As a science project, it teaches a very important practical concept, the concept of a battery. I still think it is a good buy for that reason only.
More pictures can be found:
http://watchcollectionhobby.blogspot.com/2012/06/water-powered-clock-fact-or-fiction.html
