Via Smithsonian.com
Potatoes are not only delicious, easy to grow and easy to store but scientists are now finding that their power potential is bigger than they had previously thought.
A couple years ago, researchers at the Hebrew University of Jerusalem released their finding that a potato boiled for eight minutes can make for a battery that produces ten times the power of a raw one. Using small units comprised of a quarter-slice of potato sandwiched between a copper cathode and a zinc anode that’s connected by a wire, agricultural science professor Haim Rabinowitch and his team wanted to prove that a system that can be used to provide rooms with LED-powered lighting for as long as 40 days. At around one-tenth the cost of a typical AA battery, a potato could supply power for cell phone and other personal electronics in poor, underdeveloped and remote regions without access to a power grid.
To be clear, the potato is not, in and of itself, an energy source. What the potato does is simply help conduct electricity by acting as what’s called a salt-bridge between the the two metals, allowing the electron current to move freely across the wire to create electricity. Numerous fruits rich in electrolytes like bananas and strawberries can also form this chemical reaction. They’re basically nature’s version of battery acid.The potato battery kit, which includes two metal electrodes and alligator clips, is easy to assemble and, some parts, such as the zinc cathode, can be inexpensively replaced. The finished device Rabinowitch came up with is designed so that a new boiled potato slice can be inserted in between the electrodes after the potato runs out of juice. Alligator clips that transport the current carrying wires are attached to the electrodes and the negative and positive input points of the light bulb. Compared to kerosene lamps used in many developing parts of the world, the system can provide equivalent lighting at one-sixth the cost; it’s estimated to be somewhere around $9 per kilowatt hour and a D cell battery, for another point of comparison, can run as much as $84 per kilowatt hour.