Can you power an iPod with an onion?

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?

Lemon Batteries and Potato Power

Sadly, our post-apocalyptic wanderer is in for a very disappointing evening. He or she will soon discover that attempting to power aniPod with a Gatorade-soaked onion doesn't work. Many Internet users today have made the same discovery after viewing the video in question, produced by the Web site HouseholdHacker.com.­

First, let's examine the idea of powering any electronic device with a fruit or vegetable. The concept is believable because you can create abattery with a few potatoes. This experiment is a science class favorite because it helps demonstrate how the galvanic cells that make up a car battery work.

Some batteries use galvanic cells to transfer chemical energy intoelectric energy. They depend on two metals, a cathode or positive terminal (such as copper) and an anode or negative terminal (such as zinc). These are placed in an electrically conductive solution that allows ions to travel freely between the two metals. The solution is typically an acid. Car batteries use sulfuric acid, but potatoes contain phosphoric acid, which also works. The acid steadily eats away at the zinc, a chemical reaction that releases spare zinc electrons. These electrons then join with sparehydrogen ions in the acid to create hydrogen gas.

Meanwhile, the copper isn't doing anything in its acid bath -- that is until you connect it directly to the zinc using a thin, conductive wire. The spare zinc electrons are still intent on forming hydrogen gas, but they have an easier time doing it with the hydrogen surrounding the zinc anode. So the electrons from the copper cathode travel through the wire to get to the zinc. Batteries exploit this flow of electrons, allowing us to use their combined electricity. To learn more, read How Batteries Work.

Potato batteries typically use a zinc galvanized nail and a copper penny. The two metals are stuck into the potato and connected with a conductive wire. The potato isn't the only supermarket item that meets the mandatory chemical requirements. You can conduct the experiment with any fruit or vegetable -- or an electrolyte solution such as Gatorade, which also contains phosphoric acid.­

While you'd risk damaging your iPo­d, you can connect your iPod to one of these fruit o­r vegetable batteries and get the device to register a charge 

[source: The Naked Scientists]. 

The Household Hacker method, however, falls flat for two main reasons:

1. Household Hacker tells you to "plug" the USB connector directly into the onion, but the device lacks the two different metals (such as zinc and copper) required to make a galvanic cell. Even if both metals were present, there wouldn't be enough space between the two. The Household Hacker method simply doesn't form the complete circuit required for the reaction. You'd have to take apart the USB connector and manually connect the wires to pieces of zinc and copper.

1. Even soaking the onion in an electrolyte solution would result in minimal voltage. The Naked Scientists, a group of University of Cambridge researchers who host a BBC radio show, were only able provide the 5 volts required to charge their iPod by using a dozen lemons. Even then, the charge was relatively weak. According to Naked Scientists contributor Dave Ansell, their lemon battery would have required 5,000 hours to charge their battery, and he predicted it would have most likely died within a mere 30 minutes.

Hover Shoes and iPod Tasers: Spreading Disinformation

Are the filmmakers at Household Hacker horrible at science, or do they just want everyone's iPods to smell like onions? If you're wondering why someone would go to the trouble of making such a misleading video, you have to realize that their videos are examples of disinformation.

Disinformation isn't just false information; it's intentionally incorrect data that's purposely spread to influence public opinion. This takes many forms, such as disinformation fed by a government to its citizens. Other forms, however, fall more into the rea­lms of satire, culture jamming and reality hacking. While such efforts are generally humorous, the added result is always the same: to urge the public to question accepted facts about the world by feeding them a believable lie.

The Household Hacker Web site hosts multiple videos in which an unseen, reassuring narrator guides the viewer through seemingly plausible do-it-yourself experiments. Videos claim to instruct viewers on how to bake a turkey with only a light bulb and some DVDs, how to turn an iPod into a Taser and even how to construct "hover shoes" by gluing magnets onto a pair of sneakers. Despite the ludicrous nature of these claims, many readers buy into the ideas -- either applauding the hackers for finding such cheap and entertaining shortcuts or actually attempting to carry out the experiments themselves.

If you read the user comments on the YouTube pages, you'll find numerous complaints from viewers who tried the experiments and failed to get the desired results. Various bloggers, columnists and debunkers have also failed to fly on hover shoes and power iPods on Gatorade-soaked produce.

If you actually read the Household Hacker YouTube channel, you'll find the people behind it are open about their dealings in disinformation. Their profile states, "Whether for fun or practicality; we want you to think about everything you read, hear and even see with your own eyes. You must challenge, test and innovate in every way you can think of."

The message is simple: Don't believe something just because it happens to pop up on the Internet. Don't buy into a concept just because it's presented to you as fact. Instead, test theories yourself and question the world around you. More than 6 million people viewed the video on charging iPods with onions and Gatorade. Millions may have been completely duped, but many more were forced to explore their claims and discover how batteries actually work.

So if you find yourself wandering a forsaken Earth, scavenging up old iPods for your listening pleasure, be sure to gather lots of produce, pennies and nails as well. And don't waste too much time building hover shoes.