EXPERIMENTS
On the Synchronization of Candle Oscillators
Yavor Yordanov
National High School of Mathematics and Science – Sofia (Bulgaria)
https://doi.org/10.53656/nat2021-4.01
Abstract. In this study we will investigate an interesting collective behavior of candles. It has been observed that when several candles burn close to each other they form a common flame that exhibits oscillations in size and brightness…
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Analysis of the Liquids Composition by the Sound Produced by Their Heating
Grigori Matein 1), Asen Pashov 2)
1) Atos Quantum (France)
2) Sofia University “St. Kliment Ohridski” (Bulgaria)
https://doi.org/10.53656/nat2021-4.02
Abstract. When a liquid is heated and the power of the heater is high enough (about 1MW/m2), bubbles are formed at the surface of the heater. Their expansion and collapse are the source of a specific sound, known to everybody who uses a kettle to prepare water for tea or coffee…
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FROM THE RESEARCH LABORATORIES
Calculation method for determining the gas flow rate needed for liquid removal from the bottom of the wellbore
Hofmann M., AL-Obaidi S.H., Kamensky I.P.
Mining Institute – Saint Petersburg (Russia)
https://doi.org/10.53656/nat2021-4.03
Abstract. As a result of flooding and accumulations of liquid at the bottomholes, the operating conditions of gas wells become complicated, so that they end up self-squeezing and losing of gas production…
CURRICULUM MATTERS
Project-Based Teaching in Model for Meaningful and Technological Integration of the Ecological Education
Claida Doychinova
Episkop Konstantin Preslavski Shumen University
https://doi.org/10.53656/nat2021-4.04
Absract. Project-based learning (PBL) is a comprehensive strategy for activating students‘ cognitive potential. This opens up great opportunities for a personally motivated and constructive process of learning...
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Matriculation Exams in Geography – from the Most Desired, to the Most Rapidly Avoided
Ivan Drenovski
South-West University „Neofit Rilski“
Blagoevgrad, Bulgaria
https://doi.org/10.53656/nat2021-4.05
Absract. The article provides a retrospective review of the mandatory state matriculation examinations in Bulgarian language and the second elective subject conducted in the period 2008 – 2021...
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NEW APPROACHES
Introducing High-school and University Students to Practical
Astronomy VIA Virtual Observatory Tools
Alexander Kurtenkov
Institute of Astronomy and National Astronomical Observatory, Bulgarian Academy of Sciences
https://doi.org/10.53656/nat2021-4.06
Absract. Large-scale astronomical surveys from the last decades have turned the usage of catalogs and archival data into one of the primary skills of contemporary observational astronomers...
