Our project is about investigating and analyzing how bacteria growth will affect the voltage of our organic food scrape solution. Our solution is made from food waste, garden soil, salt, and sugar and is designed to be a step in the right direction for a cleaner, greener future. We hypothesize that the solution of blended food scraps, salt, sugar and garden soil will increase the amount of voltage over the course of three weeks due to increased chemical reactions with the metals and the bacteria breaking down the organic matter within the solution, which will release electrons.

How does this solution produce energy? The solution is a somewhat a electrolytic solution as it contains water and dissolved Ions (salt) , filled with minerals and acids which create electrochemical reactions when a anode (zinc rod) and cathode (copper rod) are inserted into it. It is also a hybrid between a MFC (Microbial Fuel Cell) and a Galvanized cell as it takes components from each, such as: Zinc and copper rods which are components of a Galvanized cell. Garden soil and the decomposed food scraps produce bacteria which makes them part of a MFC. This is how they are a hybrid.

Why should you add garden soil, salt, and sugar? Garden soil typically contains bacteria that will ferment and consume the sugar and salt inside of the mixture. When the bacteria breaks down compounds inside the mixture, it releases electrons which will come in contact with metal and produce high amounts of voltage. As the bacteria continues to ferment and multiply,

What chemical reaction is happening at each electrode? The zinc rod reacts to the solutions and releases electrons which will be absorbed/transferred to the clippers attached to the rods hooked up to the multimeter to measure the voltage of the solution The copper rod receives the electrons and transfers them into ions and the cycle continues

Just to clarify if not already understood about this experiment as this part can be confusing: The rods don’t measure the voltage, they create it through reactions. The zinc is oxidized and releases electrons, making it more negative. The copper absorbs/receives electrons, making it more positive compared to the zinc. The multimeter measures the potential difference between those two electrodes. The solution has a high conductivity so it allows ion movement so the reaction can continue. Also another clarification for those who don't know much about this topic as there is a variety of words choice as sometimes we might write voltage or potential difference, but voltage is potential difference and the multimeter detects this difference in potential and displays it as a voltage.

controlled-Time of fermentation, manipulated- Type of food waste, amount of sugar, dirt, and salt. responding- The amount of voltage that the multimeter reads and the chemical reaction between the metals

MATERIALS:

• Multimeter and Connecting Wires
• Sealable Container
• Blender
• Knife and cutting board
• Flame (to heat up the mixture)
• Pot
• Eggplant Peels ( 3 Eggplant )
• Eggshells
• 2 Strawberry leaf tops
• 6 kale stems
• Tomato
• Potato (1 potato)
• 1 Banana peel
• 15 Tablespoons of salt (5 tablespoons per week)
• 15 Tablespoons of garden soil ( 5 tablespoons per week )
• 9 Tablespoons of granulated sugar ( 3 Tablespoons per week )

PROCEDURE:

1. Collect the average household food scrapes listed above (banana peels, seeds, potatoes peels, carrot peels, eggshells, etc. (Optional: Let everything decompose in one inch of water for 1-3 weeks)
2. Finely dice the potato scraps, strawberry tops, banana peel, kale stems, and tomato. Crush your eggshells and set aside.
3. Plug in your blender and set it to liquefy, high, or puree. Banana peels are quite rubbery and tough, you do not want to risk damaging the blade.
4. Add all of your food scrapes to the blender. Depending on the volume of the chamber, you may want to do this in two batches. Blend them together until the mixture is smooth and no longer has any large chunks of banana peel or eggshell. Do not worry about making it completely uniform, small clumps will decompose with time.
5. Pour this mixture into your container and add 5 tablespoons of salt, 5 tablespoons of garden soil, and 3 tablespoons of granulated sugar. Stir until incorporated.
6. Grab your multimeter and connect the clip wires to the correct holes at the bottom.( Color coded) Clip your zinc rod onto the red wire and clip your copper rod onto the black wire. Set your multimeter to volts (AC).
7. Slowly insert the rods into the mixture, ensuring that you don't get any of the solution on the clips. Stir it around and let the number settle. Record your highest, lowest, and average results.
8. Thoroughly clean the rods and your counter. If you are to wash the clips, make sure that they are unplugged and do not have any exposed wires. Close the container and let it sit in a dark humid place for one week.
9. One week later: Open the container and add 5 tablespoons of salt, 5 tablespoons of garden soil, and 3 tablespoons of granulated sugar. Stir until incorporated.
10. Remove your mixture from the container and place it in a pot. Set on high heat until boiling. It will look wrong and smell foul, but this can help increase the bacteria culture growth. Once boiling, turn off heat and repeat steps 6 and 7.
11. Replace the solution back into the original container and repeat step 8.
12. Repeat step 9, then steps 6, and 7
13. Thoroughly clean the rods and your counter. If you are to wash the clips, make sure that they are unplugged and do not have any exposed wires.
14. Dispose safely of your solution First we tested the liquid left behind from the decomposing food waste using a copper and zinc rod connect to a multimeter which had a total voltage of 0.775v , this was something like our control to see if we could the solution would produce any voltage.

To the blended solution of vegetables we added 6 tablespoons of garden soil, 5 tablespoons of salt and 3 tablespoons of sugar, which measured 0.811v

During our experiment, we observed that the decomposing food waste mixture was able to produce a decent amount of voltage when tested with zinc and copper conductive rods connected to a multimeter. First, we tested the liquid that was left behind from the decomposing food scraps before blending. When the rods were inserted into this liquid, the multimeter measured a voltage of 0.775v which acted as our control to confirm that the solution could generate electricity. After blending the vegetables and food scraps into a smoother mixture and adding garden soil, salt, and sugar, the voltage increased slightly to 0.811v. (Later on over the span of a month our final measurements were 0.780v). This showed that the added components like salt, sugar and, garden soil in the blended mixture helped improve the conductivity of the solution. The mixture had a strong odour due to the bacteria and was thick, chunky, and had a dark brown colour due to the garden soil. Through multiple experiments we found that the solutions voltage slightly decreased as the acidity that creates creates chemical reactions between the metals rods slowly dies down due to decomposition, though the bacteria still keeps the mixtures voltage quite high.

Our solution of blended food scraps was able to produce a decent amount of voltage using decomposing food scraps as an electrolytic solution. We used blended vegetable scraps mixed with garden soil, salt, and sugar to create a electrolytic solution and creating a cell that is a hybrid between galvanic and microbial cells where microbial activity and ions could generate voltage between zinc and copper metal rods. During the experiment, we observed that the solution produced a voltage that could be detected by the multimeter. The liquid from the decomposed food waste initially produced 0.775v, and the blended mixture with added soil, salt, and sugar measured 0.811v. Later on turning to 7.80v over the span of a month. This shows that the amount of voltage can increase or decreases over time as bacteria grows and the amount of acidity decreases over time. While conducting the experiment, we found that organic waste mixed with electrolytes can generate electrical energy, demonstrating the basic principle behind microbial fuel cells and bio-batteries. Some limitations of our experiment include the relatively small voltage produced and the lack of multiple trials to compare results under different conditions. Additionally, the mixture composition and decomposition stage were not strictly controlled, which could have affected the voltage measurements. Since we used simple household materials and basic equipment, the system was not made for maximum energy production. However, this model still demonstrates how organic waste can be converted into a small amount of electrical energy using common materials, serving as a useful example of how to produce energy using household food scraps.

We successfully demonstrated that decomposing food waste can generate a small amount of energy using simple household materials. Our hypothesis was that if food scraps were blended and allowed to decompose by adding garden soil, salt, and sugar, then, inserting copper and zinc metal rods into the mixture would produce voltage because microbial activity and electrolytes creating electrochemical reactions. We theorized that the voltage would increase over the course of a month, however we discovered that it actually decreased due to the decomposition of the food scraps leading to lower acidity as the fresher peels and rotten food scraps lose their acidity over time. This relates with the pre-exsisting knowledge known about galvanic and microbial fuel cells, where organic matter and bacteria help generate voltage, but the acidity is what creates the chemical reaction causing the generated voltage. By creating this solution of food waste, we better understand the real world effects of lighting and powering even the smallest of household electronics. Using this eco friendly experiment, we have shown the negative (and positive) effects of cultivating energy and learned more about the true amount of voltage required to power electronics.

By doing this project, we have widened our knowledge in the topic of renewable and biofuel energy, and with this we can teach and show others how chemical and biological processes can produce energy. If we continue this project, we could try to test different combinations of metals and different food scraps or processed food scraps vs. organic food scraps to see how these changes affect the voltage and efficiency of our experiment. We would also like to show that following our exact steps might not lead to the same results and that sizes and portion can vary and the diversity in what food scraps contain. Further research into this topic could lead us to find advances in this field research that could benefit our future world. We could improve

• Zinc and copper rods not being placed in the exact same distance apart each time, resistance in the solution would change and possibly slightly increase or decrease the amount of voltage measured.
• Different electrode surface area. If the one of the metal rods is deeper than the other leading to different exposed surfaces. This could lead to possible inconsistent readings.
• Uneven mixture of the solution. This could lead to each metal rod getting different concentrations of electrodes and Ions. Another way the mixture could be effected by this is if the water separates from the solution and dirt settles at the bottom of the mixture.
• zinc corrosion over time. we are washing both rods with dish soap and water after each use but this can still leave a possible chance of organic matter still being left on the rods leading to corrosion
• inconsistent measurements. If the added components weren't measured exactly.
• Oxygen exposure. if the container isn't sealed properly this could lead to changes in the bacteria metabolism.
• Size of vegetables can lead to changes in the mixture.

• Tips 365. What FRUIT Produces the Most Electricity?! Eggplant, Tomato, Apple, Lemon?! Banana? YouTube, 16 Jan. 2025, www.youtube.com/watch?v=0Mux8HScrTA
• Vishwanathan, A. S. (2021). Microbial fuel cells: A comprehensive review for beginners. 3 Biotech, 11(5), 248. https://doi.org/10.1007/s13205-021-02802-y
• Brilliant.org. (n.d.). Galvanic cells. Brilliant Math & Science Wiki. Retrieved February 24, 2026, from https://brilliant.org/wiki/galvanic-cells/
• LibreTexts. (n.d.). Electrolyte solutions. Chemistry LibreTexts. https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Physical_Properties_of_Matter/Solutions_and_Mixtures/Solution_Basics/Electrolyte_Solutions
• Bockris, J. O. (2026, January 29). Electrochemical reaction. Encyclopaedia Britannica. https://www.britannica.com/science/electrochemical-reaction
• BioLogic. (2024, November 15). Anode vs cathode: What’s the difference? https://www.biologic.net/topics/anode-cathode-positive-and-negative-battery-basics/

• OpenStax. (n.d.). 6.3: Galvanic cells. In Principles of Chemistry. Thompson Rivers University. https://principlesofchemistryopencourse.pressbooks.tru.ca/chapter/6-3/

  IMAGES: * https://www.freepik.com/premium-ai-image/multimeter-white-background_234648597.htm

We would like to acknowledge Aryan Sharma for the project idea and Mr. Lahoda for helping us throughout our science fair journey. And lastly our family members for providing and supporting us throughout this project.