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
