Chemistry Festival 2025
Alexandra Kamusheva,
Zlatina Zlatanova
Sofia University
https://doi.org/10.53656/nat2025-3.01
Abstract. “Chemistry Festival” is a student competition designed for students from 5th to 12th grade. The goal of the competition is to promote chemistry among young people and provide a platform for students interested in the natural sciences to showcase their talents. The organization of the competition involves prior registration of participant/participants and a supervisor/teacher; selection of a topic predefined by the organizers; and a choice of participation category: essay, poster, or presentation. The research project category is available for students in grades 8. – 12., where they present their projects on a topic related to Chemistry and Environmental Protection, using the scientific method. Participants’ work is evaluated based on predefined criteria, and those with the highest scores qualify for a defense in front of a jury. After hearing and assessing the participants’ presentations, the jury awards first, second, and third places in each category, along with special and incentive prizes.
Keywords: chemistry education; informal education; competition
The Fatal 13
Category "Essay“, 5. – 7. grade
Gincho Gichev, 7th grade[1]
Supervisor: Rositsa Stefanova
“Hristo Botev” Secondary School – Nova Zagora (Bulgaria)
https://doi.org/10.53656/nat2025-3.02
Abstract. Aluminum is a part of our lives, whether we realize it or not. Every day, we use objects that contain this metal. But behind its everyday use lies a long and fascinating history filled with scientific discovery, curiosity, and perseverance. This is what inspired me to choose aluminum as my topic: it brings together history, science, innovation, and potential for the future. In my essay, I refer to aluminum as the “Fatal 13”, its position as the 13th element on the periodic table, is “fatal” in a positive sense: it shakes up science and industry, opens up new horizons, and shown us how something unknown for centuries can become an essential part of daily life. I fully support the words of Dmitri Mendeleev: “The future belongs to this metal.”
Keywords: metal; aluminum; experiment; recycling
The Chemistry of Banknotes and Coins – Progress of Science
Category "Essay“, 5. – 7. grade
Jemal Kamberov, 6th grade[1]
Supervisor: Fatime Hussein
„Bratia Miladinovi“ Municipal School – Village Konarsko, Yakoruda (Bulgaria)
https://doi.org/10.53656/nat2025-3.03
Abstract. The paper examines the role of chemistry in the production and protection of banknotes and coins – key elements of economic life. It is explained that banknotes are made of special paper containing cotton or linen fibers, and in more modern cases – from a polymer, which making them stronger and more durable. The chemical components in these materials enable the incorporation of security features such as watermarks, microprinting and metal threads. In addition, nanoparticle inks are used to create holographic and other visual anti-falsification effects. Coins are made of metals or alloys such as copper, nickel and aluminum. Their composition is chosen based on the desired properties – corrosion resistance, strength and workability. The author shares a personal experiment with an old silver coin, which is successfully cleaned with baking soda. The conclusion is that chemistry is an integral part of creating durable, secure and modern money.
Keywords: chemistry; banknotes; coins; durability; falsification
Chemistry of Banknotes and Coins from the Time of Our Great-Grandparents to the Present
Category "Essay“, 5. – 7. grade
Ibrahim Misankov, 6th grade[1]
Supervisor: Fatime Hussein
„Bratia Miladinovi“ Municipal School – Village Konarsko, Yakoruda (Bulgaria)
https://doi.org/10.53656/nat2025-3.04
Abstract. The paper examines the importance of chemistry in the production and protection of banknotes and coins from antiquity to the present day. It describes the historical development of money – from natural materials to gold and silver coins, and later paper and polymer banknotes. It emphasizes that modern banknotes are not made of ordinary paper, but of special materials such as linen, cotton and polypropylene, which provide both durability and protection. Complex chemical inks and elements such as iron and strontium are used. Coins are made from alloys containing copper, nickel and zinc, which are resistant to corrosion. The author also shares a personal experience with a 10-lev banknote, demonstrating its chemical characteristics. The conclusion is that chemistry is an integral part of daily life, even in objects that we often take for granted.
Keywords: chemistry, banknotes, coins, gold, polymer
Chemistry of Mead
Category "Essay“, 8. – 10. grade
Gabriela Ivanova, 10th grade[1]
Supervisor: Galya Aralova-Atanasova
Vocational Secondary School of Design “Elisaveta Vazova” – Sofia
https://doi.org/10.53656/nat2025-3.05
Abstract. The paper examines the chemical, biochemical, microbiological and fermentation processes involved in the production of an ancient, long-forgotten drink that is becoming increasingly popular today - mead. Low-alcohol craft mead (13.5% alcohol) was prepared at home according to a traditional family recipe, from natural polyfloral honey produced by the family apiary. A logo of the family company that would produce the drink was created.
Keywords: mead; making homemade mead; branding
Chemistry of Banknotes and Coins
Category "Essay", 8. – 10. grade
Ivaylo Borisov, 9th grade, 9. клас[1]
Supervisor: Maya Ganeva
Secondary School with Advanced Foreign Language Studies “Dr. Petar Beron” – Pernik (Bulgaria)
https://doi.org/10.53656/nat2025-3.06
Abstract. The goal of every person is to realize themselves through the acquisition of knowledge and skills, in this sense, money is only a means to achieve goals. That is why Peter Thiel is cited at the beginning of the paper. The topic of the chemistry of banknotes and coins is interesting with the unusual connection between the familiar from daily life and the scientific processes behind them. The goal is to understand how chemical compounds are used in the creation of banknotes and how they contribute to their security, durability and aesthetic value. Information from various sources was used to describe processes such as the production of polymer banknotes, the use of security and thermochromic inks, as well as the application of fluorescent to prevent counterfeiting and fading. The results show that money is more than a means of payment: it is the product of complex chemical technology. This leads to the idea that chemistry is not just a science, but a force that shapes the world around us in an imperceptible but significant way.
Keywords: chemistry; money; banknotes; protection; technology
Aluminum – the ‘Lucky’ 13th Element
Category "Essay", 8. – 10. grade
Maria Kirilova, 9th grade[1]
Supervisor: Ralitsa Ranchova
- “Ivan N. Denkoglu” Secondary School – Sofia (Bulgaria)
https://doi.org/10.53656/nat2025-3.07
Abstract. The essay focuses on aluminum, calling it the “lucky” 13th element, because, from its discovery to the present day, it has been linked to technological progress. Its chemical and physical properties make it important and indispensable. It is no coincidence that the author uses a quote from the father of cosmonautics, Konstantin Tsiolkovsky, as the motto of the essay. The author’s dream is to explore the Universe, understand how it works, and, perhaps, discover new chemical elements or create new alloys that will help find new worlds.
Keywords: aluminum; astronautics; space research
The Metal of Time
Category "Essay", 8. – 10. grade
Hristiana Hristova, 9th grade[1]
Supervisor: Maria Stoynova
“Vasil Levski” Secondary School – Sevlievo (Bulgaria)
https://doi.org/10.53656/nat2025-3.08
Abstract. The theme of the paper is about how chemistry helped Bulgaria create its first real money, because behind each coin lies more than just metal – it carries scientific thought, political will and even a bit of national pride. The essay explains how copper, silver and gold were chosen not only for their value, but also for their chemical properties – how they react, how they are preserved and what they say about the time in which they were made. The essay shown how science and in particular chemistry helped to build a stable and sustainable currency in the Principality of Bulgaria. The essay presents interesting discoveries from archives and books are shared that show how we have used foreign technologies and knowledge while building our own monetary system. This essay is a way to show that chemistry is not just formulas, but can also tell the story of a country’s history.
Keywords: chemistry; coins; metals; copper; silver; history; Principality of Bulgaria; scientific approach
Is French Onion Soup Sweet?
Category "Essay", 11. – 12. grade
Zhenya Petrova, 11th grade[1]
Supervisor: Mimi Dimova
“St. Kliment Ohridski” Secondary School – Dobrich (Bulgaria)
https://doi.org/10.53656/nat2025-3.09
Abstract. The paper explores the chemical nature of the transformation in onion flavour during thermal processing. The aim of the study is to explain how, through chemical reactions – particularly the Maillard reaction and caramelization – onions change their pungent taste into a sweet one. The author employs a popular science approach based on literature sources and an analysis of the onion’s components (sugars, amino acids, sulphur compounds, etc.). The main conclusion is that taste is the result of complex chemical interactions that give food new properties. In this context, the preparation of French onion soup becomes an example of applied chemistry, linking scientific knowledge, sensory experience, and culture tradition.
Keywords: onion; carbohydrates; Maillard reaction; caramelization; taste; food chemistry
Aluminum – the Lightweight Heavy in Automotive Industry
Category "Poster", 5. – 7. grade
Mia Bazovska, 6th grade[1]
Supervisor: Madlena Kolcheva
- “Dimcho Debelyanov” Secondary School – Sofia (Bulgaria)
https://doi.org/10.53656/nat2025-3.10
Abstract. The poster reveals the properties and uses of a very valuable metal today – aluminum. The aim is to introduce people to this incredible metal that has been used for over 200 years, but is ideal for both modern life and the future. The first section provides information about the history of aluminum, the second discusses its use in automotive engineering, and the third focuses on its application in electric vehicles.
Keywords: aluminum; properties; automotive industry; green metal
Money – History and Necessity
Category "Poster", 5. – 7. grade
Maria Alexandrova, 6th grade[1]
Supervisor: Rumyana Stoineva
- ОУ “St. St. Cyril and Methodius” Primary School – Pernik (Bulgaria)
https://doi.org/10.53656/nat2025-3.11
Abstract. Money has accompanied human history since the dawn of civilizations – from bartering and cocoa beans to electronic cryptocurrencies. The first coins appeared in Lydia in the 7th century BC, marking the beginning of the classical payment model. With the growth of trade, more convenient forms of currency were needed – paper and later polymer banknotes. In modern times, with the development of technology, digital currencies and blockchain systems are gaining ground, with Bitcoin marking a new era in the history of money. Today, in the conditions of global digitalization, central banks are also developing their own digital currencies, shaping the future of the monetary landscape.
Keywords: barter; money; coins; cryptocurrencies; polymer banknotes; bitcoin
Chemistry of Paper Banknotes – US Dollar
Category "Poster“, 5. – 7. grade
Yoan Hashamov, 6th grade[1]
Supervisor: Daniela Baeva
“Yordan Yovkov” Primary School – Varna (Bulgaria)
https://doi.org/10.53656/nat2025-3.12
Abstract. With the development of modern technologies and the progress in chemistry, paper banknotes have become complex financial instruments that combine art, science and security. This is necessary to prevent counterfeiting and to ensure the authenticity of the currencies. To protect the banknotes, one of the most advanced technologies, such as watermarks, security threads, holograms and optical variable inks, are used. Banknotes paper consists of special mixtures that include cotton and linen to increase durability and resistance to wear. These materials make banknotes more flexible and durable than ordinary paper. To prevent wear and extend the lifespan of the banknotes, various chemicals are added, including special polymers and protective coatings. These additives also help preserve the colors and printing on the banknotes.
Keywords: banknotes; falsification; technology; ink; watermark
Aluminum – from Waste to Resource
Category "Poster", 8. – 10. grade
Stilyan Atanasov, 10th grade[1],
Nikola Ivanov, 10th grade[1]
Supervisor: Galina Kirova
“Vasil Drumev” High school of Mathematics and Natural Science – Veliko Tarnovo (Bulgaria)
https://doi.org/10.53656/nat2025-3.13
Abstract. Recycling aluminum is not just an option – it is a necessity. In a world where resources are becoming increasingly scarce and pollution is increasing, it is our responsibility to act sustainably. Our team believes that change starts with each individual‘s awareness of their responsibility toward planet Earth. Each of us can start with something small – to throw away aluminum waste in the right place, to encourage others to recycle and to support initiatives related to nature conservation. For the purpose of the study, we conducted short educational talks during school events, developed infographics that we share on social networks and prepared an online quiz for pupils focused on bauxite pollution and the benefits of recycling.
Keywords: recycling; circular economy; natural resources conservation; clean planet
The Metal of Elegance: Aluminum in Modern Jewelry
Category "Poster", 8. – 10. grade
Verka Popovska, 10th grade[1]
Supervisor: Rusanka Petrova
- “Lev Nikolaevich Tolstoy” Secondary School – Sofia (Bulgaria)
https://doi.org/10.53656/nat2025-3.14
Abstract. The paper examines the use of aluminum in jewelry on the occasion of the 200th anniversary of the metal’s discovery. It focuses on the physicochemical properties of aluminum – lightness, ductility, corrosion resistance, softness and aesthetic shine. It examines various forms of aluminum – wire, foil and powder – and their use as decorative elements. The poster also features precious stones such as sapphire and ruby, symbols of wisdom, wealth and elegance. The text emphasizes how aluminum successfully combines functionality and aesthetics, becoming a fundamental element for modern jewelry design.
Keywords: aluminum; jewelry; properties; sapphire; ruby
The Secret Chemistry of Swiss Banknotes
Category "Poster", 8. – 10. grade
Ivayla Nikolova, 10th grade[1]
Supervisor: Mariyana Georgieva
134th “Dimcho Debelyanov” Secondary School – Sofia (Bulgaria)
https://doi.org/10.53656/nat2025-3.15
Abstract. Swiss banknotes use innovative and resistant pigments to achieve rich colors and protect against counterfeiting. The yellow color of the 10-franc banknote is due to arylide yellow, a non-toxic organic pigment with excellent resistance. The red 20-franc banknote uses synthetic iron oxide and metallic pigments of aluminum and bronze, replacing the previously used toxic cinnabar. The green 50-franc banknote contains chromium oxide, a hard and refractory pigment. The blue 100-franc banknote uses phthalocyanine, a stable organic compound with unique optical properties. In addition to its technological advantages, each banknote carries a symbolic message: time, creativity, nature and knowledge - expressed through hands holding objects with deep meaning.
Keywords: color; sustainability; symbolism
Chemistry – Detective or Criminal?
Category "Poster", 11. – 12. grade
Alvina Ilin, 12th grade[1],
Valentina Tkachova, 12th grade[1]
Supervisor: Petya Petrova
- “Prof. Konstantin Galabov” German Language Secondary School – Sofia (Bulgaria)
https://doi.org/10.53656/nat2025-3.16
Abstract. The project explores the dual role of chemistry in the context of currency counterfeiting – both as a means of committing a crime and as a tool for its detection. Authors analyze the methods counterfeiters use to replicate the structure, inks, and security features of banknotes using chemicals, including polymers, fluorescent pigments, and metal compounds. On the other hand, chemical approaches for verifying authenticity are also presented, such as ultraviolet tests for banknotes and acid tests to determine the alloy composition of modern coins. The conclusion of the analysis is that chemistry is neither primarily a “detective” nor a “criminal”, but a powerful scientific tool, the impact of which depends on the intentions of the person using it.
Keywords: counterfeit; chemical analysis; fluorescence
Baby Shampoo from Edible Ingredients: Formulating a New Cosmetic Product
Category "Presentation", 5. – 7. grade
Hanna Krippendorf, 5th grade[1],
Daniel Kunev, 5th grade1
Supervisor: Tsvetelina Stoyanova
- “Todor Minkov” Primary School – Sofia (Bulgaria)
https://doi.org/10.53656/nat2025-3.17
Abstract. The aim of this pedagogical practice is to develop pupils’ interest in natural sciences through participation in practical, creative, and socially significant activities. The project demonstrates how scientific knowledge in biology, chemistry and technology can be applied in the development of a real cosmetic product with high added value and safety. Delicate baby skin requires special care and products that minimize the risk of irritation and allergies. With increasing awareness of the harms of synthetic ingredients, interest in natural and edible formulas in baby cosmetics is growing.
The study presents the formulation of an innovative cosmetic washing product – baby shampoo, created entirely from safe edible ingredients. Natural surfactants (soap nuts and Sucrose cocoate) glycerin, prebiotic thickeners and food preservatives (potassium sorbate and sodium benzoate) were used. Each component was selected for its natural origin, low allergenicity and proven benefits for sensitive skin. The final product demonstrates good washing properties and a suitable viscosity texture, while eliminating the risk associated with potentially harmful chemicals and synthetic ingredients.
Keywords: baby shampoo; natural cosmetics; natural ingredients; skin safety
The Bulgarian Name of Longevity
Category "Presentation", 5. – 7. grade
Siyana Kraishnikova, 7th grade[1]
Supervisor: Anelia Ivanova
“Konstantin Konstantinov” Secondary School – Sliven (Bulgaria)
https://doi.org/10.53656/nat2025-3.18
Abstract. Nowadays, there is growing discussion about healthy living, which is associated not only with physical activity but also with nutrition. It is important to understand which foods have a positive impact on human health—one of the key indicators of longevity. This project focuses on Bulgarian yoghurt. A study was conducted to explore its significance for a healthy lifestyle, and the yoghurt-making process was examined through experimentation. Using descriptive and comparative methods, along with analysis of conducted experiments, the project achieved its goal: testing the conditions required for yoghurt fermentation—the optimal milk temperature and environment, and the influence of different starter cultures on the process. The research concluded that effective starter cultures have a higher fat content in the milk, and that the type of culture also affects the duration of the fermentation process.
Keywords: yoghurt; fermentation; lactic acid bacteria; longevity
Chemistry of Coins
Category "Presentation", 5. – 7. grade
Kristina Ankova, 7th grade[1]
Siyana Hristova, 7th grade[1]
Supervisor: Rostislava Tsaneva
“Lyuben Karavelov” Primary School – Popovo (Bulgaria)
https://doi.org/10.53656/nat2025-3.19
Abstract. The study examines the chemical composition and structure of ancient coins, the technologies used for their minting, and the processes of aging and corrosion. Various metals and their characteristics affecting the durability and appearance of coins are presented. The role of patina as a protective layer is explained and methods for chemical cleaning are discussed. Special attention is given to techniques for determining the authenticity of coins through chemical and physical analyses. The aim is to create an idea of the interaction between chemical elements and cultural heritage, to analyze the factors that influence the condition of coins over time, to explore the possibilities for chemical cleaning and determining their authenticity, and to stimulate students’ interest in applied chemistry.
Keywords: coins; metals; corrosion; patina; dry cleaning; authenticity
Chemistry of Chocolate
Category "Presentation", 8. – 10. grade
Kamelia Vuncheva, 9th grade[1],
Maria-Sara Mandil, 9th grade[1]
Supervisor: Mariyana Georgieva
- “Dimcho Debelyanov” Secondary School – Sofia (Bulgaria)
https://doi.org/10.53656/nat2025-3.20
Abstract. Chocolate has an ancient history – from the cocoa beans of the Mayans and Aztecs to today’s global industry. In this study, we examined its composition, focusing on theobromine and caffeine – alkaloids with an effect on the nervous system. We conducted experiments to demonstrate the differences in the content of sugars and fats in dark, milk and white chocolate. We also examined the effects of chocolate’s ingredients on the human body – highlighting both the positive effects and the potential risks of excessive use. We emphasized the importance of choosing high-quality chocolate with clearly labeled ingredients, lower sugar content, no trans fats, and – of course – moderate consumption for a healthy lifestyle. Chocolate is not only a source of pleasure, but also part of the modern chemical and food industry with important social and economic importance. It is more than just taste — it is also science, from the molecular structure of its ingredients to their interactions within the human body.
Keywords: chocolate; chemistry; composition; influence; moderation
The Chemistry of Money
Category "Presentation", 8. – 10. grade
Bilyana Kurteva, 9th grade
Supervisor: Ralitsa Ranchova
127th “Ivan N. Denkoglu” Secondary School – Sofia (Bulgaria)
https://doi.org/10.53656/nat2025-3.21
Abstract. The study is related to the materials used to make modern banknotes and coins, as well as methods for protecting them from counterfeiting. Two main types of banknotes are presented – made of cotton and linen, as well as polymer banknotes made of synthetic plastics such as polypropylene. Various metal alloys used in the production of coins – copper-nickel, aluminum, bronze and steel – are analyzed, with an emphasis on their resistance to corrosion. Experiments were conducted within the project, including the study of the resistance of different types of paper in solvents, magnetic tests of coins and analysis of the fluorescence of banknotes under ultraviolet light. The presence of microbes on the surface of banknotes was also studied, as well as the influence of different materials on hygiene. In conclusion, the future of money and the role of digital technologies in their evolution are discussed.
Keywords: banknotes; coins; polymer; fluorescence
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Aluminum in Cryogenics
Category "Presentation", 8. – 10. grade
Daniel Ankov, 9th grade[1]
Iva Petkova, 9th grade[1]
Supervisor: Mariyana Georgieva
- “Dimcho Debelyanov” Secondary School – Sofia (Bulgaria)
https://doi.org/10.53656/nat2025-3.22
Abstract. This paper is dedicated to the 200th anniversary of the discovery of aluminum and explores its applications in cryogenics. Aluminum is a group IIIA metal with a constant valence of 3, and it possesses properties that make it effective at extremely low temperatures – below -150°C. Under such conditions, it retains its strength, flexibility and stability without becoming brittle. Cryogenics studies how the behavior of materials changes they are deeply cooled. Aluminum supports cryogenic processes through its high thermal conductivity, lightness and corrosion resistance. When subjected to cryogenic treatment, aluminum exhibits enhanced mechanical properties such as increased wear resistance, dimensional stability, and improved heat dissipation. These properties facilitate the creation of components that can withstand high loads, temperature stress and wear. Aluminum also supports energy efficiency and reduces the overall weight of structures, thereby enhancing the reliability and functionality of systems under extreme conditions.
Keywords: aluminum; cryogenics; low temperatures; industrial applications
Application of Aluminum in Vaccines
Category "Presentation", 8. – 10. grade
Stanislav Milchev, 9th grade[1]
Supervisor: Petya Valkova
Secondary School of Mathematics and Natural Sciences “Geo Milev” – Stara Zagora (Bulgaria)
https://doi.org/10.53656/nat2025-3.23
Abstract. In parallel with the increase in the bioavailability of aluminum, there has been a widespread increase in aluminum exposure in humans, primarily through vaccination. Aluminum salts in vaccines act as adjuvants - substances that enhance the immune response and improve vaccine efficacy. In 1926, the first aluminum-based was discovered by Alexander Glenny. Aluminum salts are widely used in pharmaceuticals due to their ability to adsorb antigens through weak interactions while preserving their structural integrity. The mechanisms of action of aluminum adjuvants include – “Depot effect”, “Pro-phagocytic effect” and “NLRP3 inflammasome”. A correlation has been found between cases of autism and “Gulf War Syndrome” and the presence of aluminum adjuvants in vaccines. The WHO issues a positive assessment of the use of aluminum adjuvants in vaccines, recognizing their benefits in the fight to protect public health.
Keywords: aluminum adjuvants; vaccines; “depot effect”; autism; “Gulf War syndrome”
Aluminum: „Wings of Humanity – Favorite 13“
Category "Presentation", 8. – 10. grade
Rostislav Stoykov, 8th grade[1]
Supervisor: Pepa Georgieva
Vocational Secondary School of Hospitality and Tourism “Acad. Nedelcho Nedelchev” – Sliven (Bulgaria)
https://doi.org/10.53656/nat2025-3.24
Abstract. In the year that marks the 200th anniversary of the discovery of aluminum, my project has conducted research that reveals what makes aluminum so special. From one to seven, I reveal that element No. 13 – the “winged”, “airy” one – has a long history, has incredible physical properties and interesting chemical properties. It is the only material that can be recycled an indefinite number of times without breaking down and still has the same qualities as the first time it was created, and is environmentally friendly. No. 13 possesses qualities that were once fiction, but are now reality. The aluminum industry is in full swing, but should we be afraid of aluminum?
Keywords: discovery; physical and chemical properties; recycling; environment; industry; health
“The future belongs to this metal.”
D. I. Mendeleev
The Chemistry in Honey
Category "Presentation“, 8. – 10. grade
Siana Karakasheva, 10th grade[1],
Simona Trichkova, 10th grade[1]
Supervisor: Maya Naydenova-Georgieva
Secondary School of Mathematics and Natural Sciences “Geo Milev” – Stara Zagora (Bulgaria)
https://doi.org/10.53656/nat2025-3.25
Abstract. Honey, known as “liquid gold,” is one of the most valuable natural food products. It has been known to humans since ancient Egyptian times. Honey is the result of the labor of worker bees. They collect nectar from plants, place it in a honeycomb cell, and seal it with wax. Through processes that occur in their bodies, the nectar undergoes a chemical transformation and becomes honey. Honey is a complex natural product. It contains over 180 individual substances, such as carbohydrates, organic acids, vitamins, and more. Its acidic nature makes it an excellent remedy against bacteria and inflammation. Due to its sweet taste, it is a widely used sweetener.
Keywords: bee honey; worker bees; nectar; carbohydrates
Use of Aluminum in Jewelry: Aluminum Wire Jewelry
Category "Presentation", 8. – 10. grade
Talisa Yakimova, 10th grade[1]
Supervisor: Galya Aralova–Atanasova
Professional School of Design “Elisaveta Vazova” – Sofia (Bulgaria)
https://doi.org/10.53656/nat2025-3.26
Abstract. The aim of this paper is to explore a rather unconventional and unexpected use of aluminum in fashion and jewelry. Fashion innovators such as Paco Rabanne, Thierry Mugler, Stella McCartney, Iris van Herpen, Gareth Pugh, and Olivier Rousteing have experimented with aluminum as a material for creating attractive, futuristic, and unconventional garments, corsets, hats, and bags. However, there is a lack of organized production of aluminum accessories, as well as established artists working primarily with aluminum jewelry. Experiments were conducted in the creation of original, author-designed, handcrafted boutique jewelry made from aluminum wire. Both the qualitative and quantitative chemical composition of the aluminum wire were analyzed, along with the physiological effects of aluminum jewelry on the human body. A logo made from aluminum wire was created for a fictional company that would produce such jewelry.
Keywords: aluminum; fashion; jewelry; aluminum wire; aluminum wire jewelry; entrepreneurship
Dairy Chemistry
Category "Presentation", 8. – 10. grade
Plamena Boiklieva, 10th grade[1]
Supervisor: Dafinka Yurchieva
Secondary School “Antim I” – Zlatograd (Bulgaria)
https://doi.org/10.53656/nat2025-3.27
Abstract. Food chemistry is a fundamental discipline that studies the composition and chemical reactions of food components during processing, contributing to the development of safer, higher-quality products. Cow‘s milk is rich in nutrients: containing water, proteins (whey, casein, milk), fats (triglycerides, phospholipids, vitamins A, D, E, K), carbohydrates (lactose) and minerals (calcium, sodium, potassium, magnesium).
Lactic acid fermentation, carried out by bacteria such as Lactobacillus and Streptococcus, converts pyruvate into lactic acid. This process extends the shelf life and improves the taste of fermented products. In cheese production, milk is curdled with yeast and calcium dichloride, which provides a stable structure. The presence of chloride ions in the brine is proven with silver nitrate. Unsaturated fats are proven with iodine, and casein is isolated and identified by Biuret and Xanthoproteic reactions.
Keywords: cow‘s milk; lactic acid fermentation; casein; unsaturated fats; cheese
Chemistry in Olives
Category "Presentation", 8. – 10. grade
Simona Gocheva, 1010th grade[1]
Supervisor: Maya Naydenova
Secondary School of Mathematics and Natural Sciences “Geo Milev” – Stara Zagora (Bulgaria)
https://doi.org/10.53656/nat2025-3.28
Abstract. The main subject of the study is food chemistry, in particular – chemistry in olives. The research begins with an introduction that includes information about the olive tree, the leading producers on the global scale and its economic significance. The chemical composition of the fruit is outlined, along with its health benefits and nutritional value. The main industrial processing stages are described: from harvesting, through lye treatment, rinsing with water, fermentation and salting, oxidation and chemical coloring, flavouring with brine until the final product is achieved. The role of the main organic and inorganic compounds such as oleic acid, phenols, sodium hydroxide, iron salts, preservatives in influencing the taste and appearance of olives is examined. An ancient processing method is also explored, in which no chemical substances are used, except for clean water. The stages of olive oil production are laid out in detail, along with a classification of different types of oil and their respective compositions. Basic knowledge is provided to help consumers select high-quality olives. Two home experiments were conducted using two types of olives to demonstrate the presence or absence of acids in the brine used during processing.
Keywords: olives; chemical composition; processing; olive oil
Chemistry of Spicy
Category "Presentation", 8. – 10. grade
Marta Pencheva, 10th grade[1]
Supervisor: Vaska Sotirova
- “Prof. Konstantin Galabov” German Language Secondary School – Sofia (Bulgaria)
https://doi.org/10.53656/nat2025-3.29
Abstract. The project examines the different types of chemical compounds responsible for the sensation of spiciness: Capsaicin (in chili peppers), piperine (in black and white pepper), gingerol (in ginger), allyl isothiocyanate (in wasabi and mustard) and allicin (in onions and garlic). Their beneficial properties and effects on the human body are also discussed. Most of them support the immune system and digestion, and some have other, more specific properties. Some myths and beliefs related to spicy foods are also examined, such as why it was believed that garlic works against evil spirits or why ginger is more useful when consumed as tea. Two experiments involving spicy foods are also presented. The first used black pepper to demonstrate how soap reduces surface tension. The second experiment examined the electrical conductivity and electrolyte properties of mustard and ginger.
Keywords: spicy; capsaicin; piperine; gingerol; allyl isothiocyanate; allicin
Jujube – Research on the Content of Vitamin C
Category "Presentation", 11. – 12. grade
Elitsa Neykova, 11th grade[1],
Elisaveta Grigorova, 11th grade[1]
Supervisor: Maya Naydenova
“Geo Milev” Science and Mathematics High School – Stara Zagora (Bulgaria)
https://doi.org/10.53656/nat2025-3.30
Abstract. The paper presents information about the jujube plant, including a brief overview of its physiology, its chemical composition, specific beneficial properties, and its use in both traditional medicine and cooking. To demonstrate the fruit’s beneficial properties, we conducted an experiment based on a global study carried out in 2013. The method is based on a qualitative test for detecting vitamin C using iodine and corn starch. First, we determined the average amount of vitamin C that reacts with one drop of iodine. Then, we experimentally estimated the vitamin C content in the fruits. The vitamin C content in the tested jujube was lower than that of the orange.
Keywords: Jujube; Ascorbis acid; Iodine; orange; Vitamin C; cornstarch
Aluminum – the Wonderful Metal that Shaped Modern Civilization
Category "Presentation", 11. – 12. grade
Zhivko Zidarov, 11th grade[1]
Supervisor: Deyan Dimchev
Private Secondary School “Leonardo da Vinci” – Dobrich (Bulgaria)
https://doi.org/10.53656/nat2025-3.31
Abstract. The main goal of the project is to demonstrate why aluminum is a material of great importance, both today and in the future. It outlines the history of aluminum – from its discovery to the present—as well as its key properties and applications. The environmental effects of aluminum production are examined, with a focus on two major challenges and possible solutions. A series of experiments were conducted to examine the aluminum’s reaction with hydrochloric acid. In addition to the interesting results we achieved (for example, burning pure hydrogen), we demonstrated the importance of using cleaning agents with caution and strictly following label warnings.
Keywords: aluminum; ecology; experiment; hydrochloric acid
Chemistry of Money
Category "Presentation", 11. – 12. grade
Iglika Koleva, 11th grade[1]
Supervisor: Emilia Ivanova
Commercial Secondary School – Burgas (Bulgaria)
https://doi.org/10.53656/nat2025-3.32
Abstract. This paper examines the chemical aspects of money as a material object in the modern economy. It focuses on the composition and structure of Bulgarian coins and banknotes, analyzing the metals, alloys, and polymers used in their production. Physicochemical methods used to protect against counterfeiting are also examined – fluorescence and inks with optical effect. Attention is also paid to the corrosion process of metals used in coins, and ways to clean them using simple chemical reactions at home. Finally, the connection between money and chemical processes in the brain is explored, with a focus on dopamine – the substance associated with motivation and happiness. The study demonstrates how chemistry not only explains the physical nature of money, but also its psychological impact.
Keywords: coins; banknotes; alloys; corrosion; fluorescence
The Effect of Marinades on Meat
Category "Research project", 8. – 10. grade
Emil Mirchev, 10th grade[1]
Supervisor: Galya Petrova
National High School of Natural Sciences and Mathematics “Acad. Lyubomir Chakalov” – Sofia (Bulgaria)
https://doi.org/10.53656/nat2025-3.33
Abstract. The present project explores the biochemical process of marination. Its aim is to demonstrate the importance of protein denaturation in increasing meat elasticity. Three types of meat are examined in eight different marinades, grouped into four categories: acidic, alkaline, alcohol, and enzymatic. The study observes how marination time and the chemical composition of the marinade affect the elasticity and color of the meat. The best results are achieved when maximum denaturation of the protein elastin occurs. It is found that marination leads to a peak in elasticity, after which renaturation occurs, reducing elasticity. This shows that identifying the marination peak is key to optimal meat tenderization.
Keywords: marination; marinade; denaturation; elasticity; meat color
Analysis of Natural Waters in the Municipality of Sliven
Category "Research project", 8. – 10. grade
Nikola Urumov, 9th grade[1]
Supervisor: Anelia Ivanova
“Konstantin Konstantinov” Secondary School – Sliven (Bulgaria)
https://doi.org/10.53656/nat2025-3.34
Abstract. The quality of natural waters and their protection from pollution is crucial for the health of people and ecosystems. Water cleanliness in Sliven is particularly relevant today, due to the presence of numerous sources of pollutants in and around the city. This study focuses on the chemical analysis of river waters in the Sliven area. The theoretical part of the research raise questions about the chemical composition and the presence of specific ions in the natural waters examined in the city. Are these waters clean enough for daily human use, and could they pose health risks such as metabolic alkalosis or acidosis? The study was conducted using descriptive and comparative methods, along with analytical and synthetic approaches. The experiment established that some rivers contain specific types of the studied ions and are classified as so-called “hard waters.”
Keywords: chemical analysis; experiments; water hardness; water purity
Can Home Tests Reliably Determine the Quality and Authenticity of Honey?
Category "Research project", 11. – 12. grade
Eva-Maria Drandarova, 12th grade[1]
Supervisor: Elisaveta Mitova
Vocational High School of Chemical and Food Technologies – Pazardzhik (Bulgaria)
https://doi.org/10.53656/nat2025-3.35
Abstract. Honey is a valuable product, known for its health benefits and unique taste. Counterfeit products are often found on the market, which may contain additives such as sugar syrup, water, and others. This study aims to compare home tests to see if they give comparable results to those from a school laboratory. Two types of honey are used for the study:
Sample 1 – The beehive is located in “Natura 2000” Protected Areas.
Sample 2 – From the commercial network, natural bee honey.
Home tests can hardly prove with 100% accuracy whether it is real or adulterated with other substances, but they can be a good guide. Comparing the percentage water content with the result of the napkin test proves that there is more water in sample 2, as does the matchstick test. The vinegar test and the analysis for proving impurities with commercial glucose reach the conclusion that sample 2 contains impurities.
Keywords: honey; quality; authenticity, laboratory analyses, home tests
The Thirteenth Element – Saver or Silent Destroyer?
Category "Research project", 8. – 10. grade
Victoria Dechkova, 9th grade[1],
Nikola Velchev, 9th grade[1]
Supervisor: Neli Ivanova
- “Ivan N. Denkoglu” Secondary School – Sofia (Bulgaria)
https://doi.org/10.53656/nat2025-3.36
Abstract. This research project investigates the impact of aluminum on human health, focusing on the potential risks associated with the use of aluminum cookware and food packaging. Aluminum is a widely used metal in the food and medical industries. Despite the long-standing belief that aluminum is safe, recent studies show that it can accumulate in the body and have neurotoxic effects. The aim of the project is to determine the presence of aluminum ions (Al³⁺) in food after heat treating in aluminum cookware and to assess the potential health risk. Through experimental analyses, laboratory studies and a sociological survey, it was found that aluminum cookware can release harmful ions, especially when interacting with acidic foods or prolonged cooking.
Keywords: aluminum cookware; health risks; neurotoxic effects; Al³⁺ ions, heat treating; acidic foods
