Reflect and Share

My final product

Why the product did not work?

Hypothesis #1 – Something was wrong with copper and aluminum strips

As I mentioned before, due to the absence of copper and zinc strips, I made the strips by taping copper tape and aluminum foil on a metal board. Since the strips were not made by accurate and professional machines or people, I could not determine whether the strips were suitable for this device. This is why I could not avoid the possibility of strips having a problem.


Hypothesis #2 – Voltage from the lemon battery was not enough to run a motor

This is the initial concern that I have considered from the beginning of the project. I was optimistic about this obstacle as I believed the motor would work, but the speed of the motor might be slow. Speed does not need to be fast in the carousel, so I ignored the problem.


To find out which one was the problem that disabled the product, I used a voltmeter to measure the voltage produced in the circuit. If the voltage is not observed, there is something wrong with the strips. If the voltage exists at a low rate, the lemon battery or the number of lemons is not enough to produce enough voltage to run a carousel. If the voltage is high, everything gets totally wrong, and there is a problem that I can even define.

Running the voltmeter told me that the problem was in the lemon battery not providing enough voltage to the carousel.


I used three lemons to actuate the carousel, but it still did not work.

Then, I came up with a question, “Will the product work if I put enough lemons in the circuit?”


Research about “Will the product work if I put enough lemons in the circuit?”

I found a post of a student that questions precisely what I asked. The student was doing a lemon battery experiment and tried to run a motor with the battery. She increased the voltage by 12.98V using a serial connection method, but the motor, which works with a single 1.5V battery, did not work.

Staff from the Korea Institue of Energy Research gave a reply to the question. What he said is:

A certain amount of voltage and electric current is required when running an electric device. In your case, it seems that the circuit’s voltage is high enough to actuate the motor as plenty of lemons are serial connected. Then, the problem would likely be in the intensity of the electric current, as it is expected to fall short to operate the motor.


My analysis

Rephrasing the word from the staff, even though the voltage was high enough, the intensity of the electric current might fall short due to the increased resistance. This is happened because of a special relationship between the intensity of electric current, voltage, and resistance.

Ohm’s law explains the relationship between the three components. Specifically, the first formula [V=IR] shows if the voltage is constant, the intensity of electric current decreases when resistance increases. Using the serial connection, the voltage was high enough in the lemon battery. However, resistance also increased hugely because it took too many wires to create a serial connection. Consequently, the intensity of the electric current cannot increase.

Therefore, to answer my research question, it turned out that increasing the number of lemons would not help running the motor as while voltage increases, resistance also gets more extensive and does not let the intensity of the electric current increase.


Reflection on my skills

I had a clear division of success and struggle throughout the project. The successful part is 3D modeling the pieces. Although the project requires precise and accurate measures and calculations, I modeled 5 works without a significant error. This allowed me to save time and use it in other sections. The field that I need improvement in is assembling the pieces. It was obviously the most challenging part. I took multiple classes to straightly align the shaft of the motor and pillar. It took 30min-1hour to stick horses on the bottom of the roof. Throughout the project, I acknowledged that my weakness was in manufacturing skills. I might spend less time planning for further projects while providing more building time to cover my manufacturing skills.