Fruit Battery Experiment
by: Daniel Lee
Purpose of the experiment: To determine which fruit produces the most electricity.
Hypothesis: lemon produces the highest voltage.
Materials: various kinds of fruit, 4 pieces of copper, 4 pieces of zinc, 5 electric wires, and an LED lightbulb.
Variables:
Independent variable: types of fruits.
Dependent variable: brightness of the LED/ voltage produced.
Controlled variables: connection of fruits, type of LED.
Method:
1. Insert a piece of zinc and a piece of copper in each fruit.
2. Connect fruits through electric wires.(zinc = negative side, copper = positive side; the direction should be + to -. So connect copper to zinc)
3. Arrange the fruits in series: one end of the chain has a zinc electrode, the other end has a copper electrode. Connect both ends to the LED (copper side to the longer leg/anode, zinc side to the shorter leg/cathode).
4. Compare the brightness of LEDs and measure the voltage of the fruit from different types of fruits. (I used 4 lemons, 4 limes, and 4 oranges.)
5.
Results:
1. Lemon: 0.73V
2. Orange: 0.84V
3. Lime: 0.76V
According to the results, oranges produced the highest voltage and lemons produced the least voltage, which was the exact opposite of my expectation.
Explanation:
The fruit’s juice contains acid, which helps move tiny charged particles called ions between the metals. This movement of ions creates an electric current. When the fruits are connected in a row, their voltages add together. If it becomes a sufficient amount of voltage then the LED lights up. Also, if the wire connects the same metals, then the electricity will not flow because electricity only flows from + to -; electricity only flows if the wire connects different metals (zinc to copper). But if the wire connects zinc-zinc(+ to +) or copper-copper(- to -), the electricity would not flow.
Further Investigation / Improvements:
It will be better to use more fruit than 4 because when we used less than 4 fruits, the LED light didn’t light up due to the lack of voltage. Also, more fruits show the difference of the lights more clearly. For the further experiment, I could test the combination of other different fruits and check the difference of the electricity produced.
