This is a cute little toy car that came into my possession just recently. This is a very special toy car, as it runs on saltwater instead of using batteries! It was a free gift by Shell during an event known as the Make The Future Singapore
A little background…
Make The Future Singapore is an event that happened over the March holidays, an event that talks about bright ideas to solve energy challenges of the future. An interesting idea that I saw during the event is Zorb Balls, which converts kinetic energy into electrical energy with the use of a giant ball.
This picture is taken when I was running inside >.< Comparing left and right, doesn’t it look similar? I finally understand how a hamster feels when it is running inside the ball (dizzy… D:)
Back to saltwater car…
So how does this saltwater car links to solving future energy problem? It can be used as a renewable source of energy. But how does it work?
Science behind the saltwater car
The principle behind the saltwater car is Electrochemistry, when electricity is generated based on the movement of electrons between different electrodes (conductor), similar to how a battery works. Electrons move from a more reactive electrode to a less reactive electrode, and the reactivity is based on the reduction potential of the metal/carbon (reduction potential is the tendency to gain electrons and thereby being reduced). The more reactive a metal is, the lower the reduction potential. An electrolyte (a solution that conducts electricity) is required to connect the 2 electrodes together to close the circuit. The overall circuit is known as a voltaic cell. A common example used to illustrate this voltaic cell is the lemon battery, where citric acid in lemon acts as the electrolyte.
Looking at the assembly of the car, the motor is connected to 2 plates, one black and the other shiny. The black plate is carbon while the shiny plate is a magnesium, separated by a piece of filter paper. When saltwater is added to the filter paper, it acts as an electrolyte to close the circuit and power up the electrochemical reaction. Since magnesium is more reactive, magnesium (anode) will lose electrons to carbon (cathode) and thus electricity is generated to turn the motor. There we have it! A car powered by salt water!! Since 72% of Earth is covered by water (and 97% of which is sea water), could we actually power our future cars with sea water? Hmmm…