Results
Potato – 0.4 volts
Apple – 0.3 volts
Lemon – 0.3 volts
For the lemon we found that putting it upside down was a more effective way of measuring the voltage.
Additional observations
We found that putting the nail and the copper strip closer together made the measurements more effective in each fruit/vegetable.
Explanations
The potato ended up having the highest voltage which was surprising because I expected the lemon to have the highest voltage, the lemon has the most electrolytes, but the potato ended up having the highest voltage. The reasoning towards why the potato had the highest voltage is unknown.
Questions
What is causing the flow of electrons?
The closed circuit with the fruit creating the voltage causes the flow of electrons.
What are independent, dependent, and controlled variables in this experiment?
Measuring the voltage, the fruit and the copper strip and the nail.
How can we modify our experiment to improve our results?
Use a bigger variety of fruits and vegetables.
What are sources of error or uncertainty in our experiment?
If the ripeness of the fruit and vegetables were different it could’ve impacted the outcome.
How can I use this in my every day life?
If I lived in a rural area and we had a lot of fruit and no power we could use this experiment for power.
Very good post outlining the learning you gained from creating your own battery with fruit. Isn’t it interesting what came out as the best electrolyte? It has to do with something called the Van’t Hoff Factor. Consider checking it out if you want to know more. Great job!