Elec-citrusy: turn lemons into batteries

If there's two things I know kids love, it's fun science experiments and lemons. Well, maybe not so much eating lemons, but I'll bet my bottom dollar they'll enjoy turning one into a battery.

The concept behind this experiment is simple: take two metals that spit electrons at each other (in this case, zinc and copper), shove them into opposite ends of a lemon, and the acidic juice inside the fruit will help create a low-level current. If you're not already familiar with this great little science project, grab a few kids, a couple lemons, and let the LED-lighting madness begin!

Materials

1. Three or four big juicy lemons
2. Zinc-coated nails (one for each lemon)
3. Pennies older than 1982* (one for each lemon)
4. Common electrical wire
5. A red LED bulb
   

Tools

1. It's not completely necessary, but a multimeter will help you determine if one of your lemons is... well, a lemon (as in, a dud).
   

Time

About 30 minutes.


Steps

1. Grab a lemon.
2. Stick a nail in one side and a penny in the other.
3. If you have your multimeter handy, test the two contacts (nail is negative, penny is positive) and see if they register a current.
4. Repeat steps 1 through 3 for each lemon.
5. Once all the contacts are placed, begin connecting the lemons with your wire. Connect each lemon together by their opposite contacts (positive to negative).
6. After you've connected all the lemons, you should have one positive and one negative contact left open on each side of the lemon chain.
7. Attach wires to each open contact, and then test them on your LED.
8. Polarity is important on an LED bulb, so make sure you have the correct wires attached to the LED contacts, or else it won't light up.
9. If you wired everything correctly, and your lemons have enough juice, you should be able to make the LED light up (albeit a bit dimmer than you might expect).

For a more in-depth look at this experiment, as well as an awesome video, check out this site. If you're not a fan of lemons, but would still like to create your own battery with everyday household items, try substituting the lemons with potatoes or vinegar (a DIY Life favorite). And for those parents out there who shy away when they hear the words "electricity" and "kids project" mentioned in the same sentence, fear not -- this project barely generates enough electricity to jump start a flea motorcycle (whatever that means). Long story short, it's safe, fun, and educational... and you can put the batteries in your iced tea when you're finished!

* From 1962 until 1981, US pennies were made from a mixture of 95% copper / 5% zinc. In 1982, however, the tables turned and pennies were made from 97.5% zinc / 2.5% copper, which is too low to work for this project.