site.btaBulgarian Students Win Two Medals at European Olympiad in Experimental Science

Bulgarian teams won two silver medals at the European Olympiad in Experimental Sciences EOES 2025, which was held from April 26 to May 3, 2025 in Zagreb. A total of 48 teams from 23 European Union Member States and one visiting team from Ukraine participated in the competition. Each team consisted of three students up to the age of 17, said the Education Ministry on Saturday.

Bulgaria was represented by two teams. Team A was represented by Yordan Petkov (physics) from the American College in Sofia and two representatives of the Sofia Mathematical High School, Damyan Ivanov (chemistry) and Teodor Petrov (biology). Team B was represented by Rayan Kamarinchev (physics) from the High School of Natural Sciences and Mathematics in Sliven,, Teodor Kusev (chemistry) from the National High School of Mathematics and Science  in Sofia and Melih Osman (biology) from Ardino. The participants were selected among the winners of the national chemistry and biology olympiads and the national autumn physics competition.

During the first competition day, students solved tasks related to the application of various methods for the study of fresh and salt waters. Among them were the assessment of their quality through taxonomic ecological parameters, the determination of iodine in salt produced in the salt pans of Croatia, as well as the influence of salt concentration on the optical parameters of water.

In the second round, the tasks were dedicated to kinetics and speed. The students studied the influence of air resistance on the periodic motion of bodies. Using a spectrophotometer they made, they determined the speed of the reaction of conversion of different forms of dyes. Using the same dye, the students determined the speed of the metabolism of microorganisms and its influence on food quality. The students had to apply various analytical research techniques: spectrophotometry, microscopy, taxonomic determination, titration, electrical and optical measurements.

The team leaders were: Assoc. Prof. Dr. Hristina Andreeva (Physics, Coordinator for Bulgaria, Sofia University and Institute of Electronics of the Bulgarian Academy of Sciences), Senior Assoc. Prof. Dr. Kalina Pachedjieva (Biology, Sofia University) and Vladimir Tsvetkov (Chemistry, Ronald Lauder Private University). Assoc. Prof. Dr. Denitsa Teofanova (Biology, Sofia University ) also participated as an observer in connection with Bulgaria's upcoming hosting in 2027.