Fruit/Battery Experiment

We utilize all sorts of batteries throughout our everyday lives. Cars, cellphones, and digital watches are all powered by some sort of battery. With that said, we were curious what kind of basic principles create a “battery.” A battery is a container that consists of one or more cells that produce an electro-chemical reaction when connected to a device. The experiment we chose was to create a battery out of a fruit (lemons, limes, oranges, bananas) using carbon as the constant element and switching out various conductive metals (zinc, copper, iron) as the second element. We hypothesized that the lemon would have the highest pH level and thus would generate the highest amount of voltage. Conversely, we had guessed that a banana would produce the least amount of voltage. For the experiment, we utilized a multi-meter to measure the voltage of each fruit and metal combination. Our results were fairly surprising. On average, copper was the least conductive metal – generating only .1 volts when implanted in a lemon. The galvanized (zinc-coated) nail produced the highest readings – producing .84 volts when implanted in an orange. The most surprising aspect of our findings was that the banana produced fairly high readings on the multi-meter. This is because the ascorbic acid found in a ripe banana tends to have a fairly higher pH level than the citric acids found in the other fruits.

     
The basic principle behind creating the 

voltage is a transfer of electrons in a process known as oxidation. While zinc is entering the acidic solution, two positively charged hydrogen ions from the electrolyte combine with two electrons at the carbon’s surface and form an uncharged hydrogen molecule.

The reasoning behind conducting this experiment is to see if the acquired voltages would be adequate enough to power a small device. For instance, a small flashlight requires roughly 1.5 volts. The highest voltage we recorded was created by citric acid from the orange and the zinc-coated nail. The voltage was .84. We realized that this method was not successful in powering a device, however if we were to implant a higher amount of zinc – the voltage would likely be high enough to power a small flashlight.

Group: 
Brian Brewster, Kim Wallace, Joe Cesaro, Joe Scolley