Middle School Student Creates Renewable Energy from Organic Waste

This middle school student explored real-world renewable energy with a biofuel project for the science fair.

Clean Energy at the Science Fair

Sara Angarita will soon be starting eighth grade in Bucaramanga, Colombia. For the last three years, she has participated in the school science fair with projects from Science Buddies. This year, she explored biofuels and won first place at her school science fair after advancing from classroom presentations.

Investigating Real-World STEM

Students who have a personal or community connection to their topics often find the science fair process more rewarding. Sara says her interest in biofuels was partly inspired by having parents who work in STEM, but her project was also fueled by real-world challenges related to renewable energy.

What are biofuels? Biofuels are a potentially powerful and sustainable source of renewable energy. Food scraps, dead plants, sawdust, and other decaying organic matter are collectively called biomass and are a rich source of energy. You can get energy from biomass by burning it, turning it into a liquid, or converting it into a gas called biogas.

We asked Sara to share more about her project, why she chose to explore biofuels, and how the experiment went.

What made you choose the From Trash to Gas: Biomass Energy project?

"I chose the biogas project because Colombia produces a lot of agricultural and livestock waste, and many people are interested in turning these residues into renewable energy."

Is this an area of science you were already interested in? If yes, why?

"Yes. I like learning about renewable energy and environmental solutions. Both of my parents are chemical engineers. My father works in bioenergy, so I became curious about how organic waste can be transformed into useful energy. I think it is amazing that microorganisms can transform organic waste into biogas that can be used for cooking, heating, or even generating electricity."

How did the project go? What did you learn or discover?

"The experiment worked, and I was able to clearly observe biogas production using balloons attached to the bottles. I tested different concentrations of cow manure mixed with banana and vegetable peels. My best result produced about 233 cm³ of biogas in seven days.

I learned that mixing different types of biomass can increase biogas production and that temperature is very important for the microorganisms that produce the gas."

Above: Sara presenting her project (left) and with her first-place award (right).

What was the most challenging part of the project?

"Temperature strongly affects anaerobic digestion. The most difficult part was maintaining a good temperature for the microorganisms.

Another challenge was that my first experiment did not inflate the balloons, even after about 20 days. I adjusted the biomass concentrations and repeated the experiment until I was able to clearly observe biogas production."

(Because temperatures were colder in the morning, Sara took extra steps to warm the mixtures in the morning and evening.)

An initial setback like that after several weeks can be frustrating. What kept you pushing to find a solution and retest?

"I wanted to understand why the first experiment did not work because I knew biogas production should happen with cow manure. I did not want to give up without trying to improve the experiment first."

What was the most rewarding part of the project?

"The most exciting moment was seeing the balloons inflate. It was very satisfying to finally observe the biogas forming. It was also interesting to see how the concentration of cow manure and banana affected the results and how important temperature was."

Was this your first science fair?

"No. I have participated in science fairs before, and I have also used Science Buddies projects in previous years.

In 2025, my teammate and I did a project inspired by the Seed Paper experiment. We studied how slow-release and liquid fertilizers affected plant growth when using recycled seed paper. That project won first place in our category, and we still have the calendula and basil plants that grew from the paper we made.

In 2024, when I was in 5th grade, we did a project about turning milk into plastic. That project won second place at the science fair."

Is biogas a topic you will continue to investigate with your 8th-grade project? Or are there other areas of STEM you are interested in exploring?

"I would like to try a different kind of project next year because there are many areas of science I still want to explore."

Is there anything else you would like to share about your project?

"This project helped me understand that organic waste is not just trash. With the help of microorganisms, it can be transformed into a valuable renewable energy source like biogas. I am very grateful to Science Buddies for providing project ideas that help students explore science through real experiments."