The Mythical Water Clock

Picture courtesy of bedol®

Water Clock - A story of a failure-ridden project



In the 2nd week of our semester 1, we were divided into groups and given a dozen of projects to choose from. There's a challenge to find an alternate way to replace the big and bulky water dispenser bottle.

Another challenge is to come out with a way to measure the content of a gas cylinder tank. Stirling engine, XY table, which is basically a machine that can go X and Y direction, bladeless fan, water clock, etc etc. And so we thought that the water clock would be an easy project. It does sound easy, up until we get hands-on.

Our objective is to build a clock that runs on water, be it chemically, electrically, or mechanically. Sniffing around the internet, there seems to be a real water clock in the market. Manufactured by a company called bedol, it is claimed that all you need is just water to power this fancy looking device. Plain water. No additives. They even sell alarm version of this clock. So how does this magic work?


The theory is simple: the water you pour in acts merely as an electrolyte to initiate a chemical reaction inside the clock, which involves a zinc plate, and produces electricity to power the digital system. In layman's term, it is called electrolysis. Downside is that the zinc plate will be eaten up slowly, and you will have to change it. So strictly speaking, this is not a 'water powered clock'. Should have called it 'Electrolysis Clock'. There is a blog debunking this myth. According to the manufacturer website:


'How does it work? Magic mostly. And a little bit of science too. 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.


Sounds magical, but try reading this blog. The so-called 'fuel cell' is nothing but zinc plates. -.-"


More sniffing in the net and we found something rather different (a bit). This time, you don't just pour in plain water; you pour water and lemon juice (or any citric juice)! Now this is a very simple and common experiment done by almost every students who have studied science in primary or secondary school. We know that the acidic property of citric juice makes it act as an electrolyte. You stick zinc or copper plates into the lemon and voila! The clock starts to tick. Nothing magical also.

So is there any clock that really runs on water? Yes there is. Back in the Egyptian era, they built a clock called clepsydra or literally water thief, which managed to indicate time by using water. I can't find any more information about this type of clocks, but according to some sources, they are powered by gravity and siphons. Hmm....

Enough about the real water clock. What about ours?

First we came out with an idea of using siphon to pull water from lower to higher ground, flow out the water to turn a turbine which is then used to turn the gears of a mechanical clock. More researching and we found out that mechanical clock is simply too complicated, and there is no possible way to pull the water from lower to higher ground, thus defying gravity. Simple experiment showed that the turbine has to spin at very high speed (theoretically as fast as a Tamiya) in order to generate enough electricity to power a simple digital clock.
First concept out.

Second, my brother came out with an idea of implementing hourglass design that has to be turned every once in a while. Evaluation showed that we can't make it self-rotating. Even if we did manage to make it self-rotating by inserting magnets, the hourglass would spin crazily like Tamiya motor too. And we can't make the turbine to spin at light speed either.
Second idea out.

Then we found a video on Youtube, showing probably the simplest water clock. By implementing see-saw concept, they placed a bottle upside-down at one end of the see-saw to make it drip water into another cup on the see-saw, so that the weight of water would pull the see-saw down, and the other end of the see-saw will indicate and count a certain period of time. It's a good idea, but they're actually making a 'water powered stopwatch'.

Last week we were trying to redesign the see-saw concept into a 'ferris-wheel' structure so that the wheel would spin very slowly, indicating the hour similar to a clock face. Experiment showed that the wheel spun very fast and uncontrollable, so that idea is kicked out. But the fast spinning wheel might work if we use some gears to slow it down, making it spinning at 1 teeth per second/minute/hour, building something similar to a simple mechanical clock, but without the pendulum as timekeeper.


Hopefully it will work. I will update about our progress. IF we have any progress.