Imagine an Earth cast back into the darkness of prehistory. The world's power grids are cold, the roads still and lifeless with rusting traffic jams. The nights are once again black as pitch, spotted only by the lights of distant campfires. Like the other few, scattered survivors, you scrape through the rubble for survival as best you can. Then one day, things get worse. You're listening to a great two-hour DJ mix when suddenly the battery of the iPod Classic you found begins to die. You panic.
After all, there's still 45 minutes remaining on that mix, and it was more than half-charged when you fished it out of some wreckage the day before! You empty your knapsack onto the ground and, fumbling through your possessions, discover there's still hope.
Wrapped in a napkin, you find the onion you were going to boil for supper. You pull out your last jug of Gatorade, along with the cooking pot and screwdriver you keep on your belt. You untie the iPod USB cord from your long, ragged hair and arrange the items in front of you. Finally, you pause the mix, place the iPod on the ground and run through the instructions in your head again -- instructions you watched, back before the chaos, on an old YouTube video.
It's a simple principle, as you remember it, working along the same lines as those batteries children would create with potatoes in science class. Gatorade and other sports drinks contain electrolytes, electrically charged mineral salts such as sodium, calcium and potassium. Normally, those electrolytes recharge our body, but they should recharge a battery just as easily, right?
First you'll have to poke two holes, one in each side of the onion, with your trusty screwdriver, then soak it for about half an hour in Gatorade. After you dry off the onion, you'll plug one end of the USB cord into the iPod and one into the vegetable.
You stare nervously at the flashing battery icon. Will it work? Or will you be sitting in silence again tonight, eating onion and Gatorade stew and hoping against hope to find another MP3 player in the wreckage of the next apocalyptic ghost town you wander into?
Read the next page to find out.