Teen Tech Tip #31: Zinc and Copper Make Battery Cells Elemental  
Welcome back to the blog. This week involves a really fun experiment that lets us see the basics of how batteries work. First, check out his video from Rig it Yourself 101.

What's Going on Here?!

It is pretty simple actually. We have three different common household fruits: banana, orange and apple. Copper (Cu) and Zinc (Zn) nails are inserted into the acidic fruits (apple and orange) and the nails are connected through the banana with small metal wires. Lastly, a simple 5 Volt USB cable is being used to charge an iPod.

So How Does It Work?

The energy that we get to charge our iPod is coming from an electron exchange in the metals between the fruits. Both nails are undergoing a chemical reaction caused by the acid in the citrus fruits. The Zn atoms are being dissolved into Zn ions that are positively charge (give two negatively charged electrons). The Cu nail has an oxidized tarnish (Copper Oxide) that dissolves in acid. The Copper ions attract the negatively charged electrons to neutralize the ions into Cu metal.

The banana is necessary, because it is relatively neutral (pH) and will continue to conduct the electron flow. This creates a circuit. The USB cable is able to enter the circuit and continue the electron flow and receive enough of an electrical charge to briefly charge an iPod.

How Does this Compare to a Battery?

Technically this would be considered a fuel cell, but the idea is very similar. In fact, the type of fuel cell that we see created is very similar to the very first chemical battery invented in 1800 by Italian physicist Count Alessandro Volta, namesake of the volt. His design is the foundation for the modern battery.

Check Out These Resources for More Information:

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  • Fuel Cell
  • Volta, Alessandro

  • gold tips 
    Nice article ....thanks for sharing with us

    caleb peterson 
    so cool. good science fair project. i got to try this!

    That is amazing.

    This sounds very cool! I didn't know you could charge something with fruit. I can share this information with my friends now. They'd be interested too!

    this is so cool I'm going to try this

    Seth Cobb 
    I think this is really cool. At first, I thought that only oranges, lemons, and potatoes had electrolytes in them (this knowledge coming from a science project I did in fourth grade, where I used lemons to power a small watch). I didn't think you could use other fruits to generate electricity as well. An interesting experiment. I also like the idea of using the nutritious contraption as a primitive, but useful, "fuel cell". This will expand the array of fruits that kids commonly use as science projects for school; potatoes are classic, its nice to see some more fruits and vegetables come into play.

    Mae Burns 
    I think this is REALLY cool and I'm going to try this soon! It's also truley amazing how you can charge an ipod without using electricity. I personaly thought it couldn't be done but there it is! Being done! THIS IS SOOOO AWESOME!!!


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