rss_2.0Chemistry-Didactics-Ecology-Metrology FeedSciendo RSS Feed for Chemistry-Didactics-Ecology-Metrology 's Cover of CO in Boudouard’s Reaction as an Example of Reversible Chemical Reaction<abstract><title style='display:none'>Abstract</title><p>One of the fundamental elements of a scientist's work is the ability to lead observations of the phenomena that surround us and based on them making conclusions. These observations are conducted within the so-called scientific experiments. Lessons learned based on the results obtained in experiments allow researchers to better understand the essence of the phenomena occurring in the world around us. Drawing conclusions is not always easy. In order to achieve this skill, we must possess a well-established knowledge in the field of the phenomenon that interests us. The most striking example of how important skills are observation and drawing proper conclusions is the phenomenon of global climate warming. The main parameter influencing temperatures registered on Earth is the concentration of greenhouse gases in the atmosphere, and especially carbon dioxide created from combustion processes. A significant role in studies of the reduction of CO<sub>2</sub> emissions plays chemists. To be sure that conducted by them experiments are optimally designed, it is necessary to ensure them with proper education already at the secondary school level. The main aim of this article was to conduct the study in order to explain chemical issues that create the greatest cognitive difficulties among students. The second aim of the article was to propose a chemical experiment to students that would allow them to find out more about the phenomena governing in the area of problematic issues. The proposed experiment is based on the concept of solubility equilibrium. Results of preliminary tests that have been carried out after applying this experiment on a small group of students, indicated their better understanding of the studied subject.</p></abstract>ARTICLE2021-01-29T00:00:00.000+00:00Determining Cellulolytic Activity of Microorganisms<abstract><title style='display:none'>Abstract</title><p>Decomposition of cellulose to glucose requires complex cooperation of glycoside hydrolase enzymes. As a result of glycoside β-1,4 bonds hydrolysis, shorter chains of cellulose, oligodextrin, cellobiose and glucose are created. A number of bacteria and fungi demonstrate the capacity to degrade cellulose. Their activity can be assessed with the use of qualitative and quantitative methods. Qualitative methods with the use of e.g. Congo red, are used in screening studies, however, they do not provide information about the quantity of the produced enzyme. Spectrophotometric methods are more accurate and they measure the quantities of reducing sugars with the use of appropriate substrates, e.g. carboxymethylcellulose is used to determine endoglucanases, avicel cellulose to determine exoglucanases and Whatman filter paper to determine total cellulolytic activity. Activity of microorganisms depends not only on their species or type but also, among others, on substratum composition, cultivation conditions and the appropriate selection of parameters of the carried out enzymatic reactions.</p></abstract>ARTICLE2021-01-29T00:00:00.000+00:00Lower-Secondary School Chemistry Textbooks’ Didactic Equipment<abstract><title style='display:none'>Abstract</title><p>Textbooks’ fundamental influence on teaching is caused not only by their subject matter, but also by their didactic elaboration. Textbooks’ individual functions are fulfilled through incorporated structural elements. Their pool is referred to as the didactic equipment of the textbook and represents qualities of the textbook through the options it gives to its users. The presented overview of lower-secondary chemistry textbooks’ didactic equipment included 7 series of currently available textbooks. Results of the analysis serve not only as a possible guide for chemistry teachers’ textbook selection, but they also provide insight into the current state to authors of textbooks and other didactic materials. Chemistry textbooks for lower-secondary schools achieve relatively high didactic equipment (75-92 %). The best equipped are the series of textbooks published after the current state curriculum introduction (by publishing houses Fraus and Nova Skola). Surprisingly, however, the most recently published textbooks by the Taktik publishing house showed the lowest didactic equipment.</p></abstract>ARTICLE2021-01-29T00:00:00.000+00:00Pupils’ Preconceptions About Heat, Temperature and Energy<abstract><title style='display:none'>Abstract</title><p>This article is focused on finding out pupils’ preconceptions about heat, temperature and energy. As a research tool we used a didactic test with individual types of tasks about the concepts. A total of 122 respondents aged 12 to 14 participated in the research. The research sample consisted of two groups of pupils. One group consisted of pupils attending a school assigned for talented pupils, for simplicity they are referred as talented pupils. The second group consisted of pupils who do not attend this type of school, we marked them as “general population”. The number of respondents in the sample of talented pupils was 54. The number of respondents in the sample “general population” was 68 pupils. In the research we compared ideas about concepts heat, temperature and energy of talented pupils and pupils of the “general population”. We also compared talented pupils and pupils of the “general population” in solving of conceptual and algorithmic tasks in didactic test. We found out pupils of the age from 12 to 14 have misconceptions about the concepts. We also identified the misconceptions and the most common are also mentioned in this article.</p></abstract>ARTICLE2021-01-29T00:00:00.000+00:00Study on Toxicity of Biometal(II) Monensinates Against Rat Zajdela Liver Tumour<abstract><title style='display:none'>Abstract</title><p>The ability of Monensic acid A (MonH∙H<sub>2</sub>O) and its neutral metal complexes [M(Mon)<sub>2</sub>(H<sub>2</sub>O)<sub>2</sub>]with ions of Mg<sup>2+</sup>, Ca<sup>2+</sup>, Mn<sup>2+</sup>, Co<sup>2+</sup>, Ni<sup>2+</sup> and Zn<sup>2+</sup> to decrease viability and proliferation of primary cell cultures, originating from a chemically induced transplantable liver tumour of Zajdela in rats, and bone marrow cells from the same tumour-bearers, was evaluated. Experimental data revealed that manganese(II) and nickel(II) complexes of Monensin A are relatively more selective against the tumour as compared to the healthy bone marrow cells.</p></abstract>ARTICLE2021-01-29T00:00:00.000+00:00Water Quality and Ichthyofauna Habitat Conditions in Lake Czolnowskie (N-W Poland)<abstract><title style='display:none'>Abstract</title><p>Increasing anthropopressure affects natural ecosystems and may express itself in regional or spot contamination of water and soil environment. The quality of ground and surface waters depends to a large extent on drainage area management, where biogenic substances (i.e. nitrogen, phosphorus and potassium) are transported with surface run-offs to the environment. The article discusses results of studies on the drainage area of Lake Czolnowskie (Zachodniopomorskie Province). Studies covered physical and chemical assessment of soil conditions and water quality; additionally, fish was caught using two independent methods - gillnets and power generator (pursuant to CEN EN 14011 2003 and PN-EN 14011 2006). Results obtained confirm regular run-off of biogenic materials from the surface of farmed drainage area to Lake Czolnowskie. During the period of studies, the reservoir was exposed to i.e. reduction of water oxygen (3.56 mg/dm<sup>3</sup>) and permanently elevated level of general phosphorus (0.15-0.27 mg/dm<sup>3</sup>) and ammonium acid (0.16-0.27 mg/dm<sup>3</sup>), which degraded the quality of life for ichthyofauna inhabiting the lake.</p></abstract>ARTICLE2021-01-29T00:00:00.000+00:00Human Resources and R&D at the Institute for Nanomaterials, Advanced Technologies and Innovation (TUL)<abstract><title style='display:none'>Abstract</title><p>Within the next few years, Europe’s economic paradigm will change fundamentally. Its manufacturing base will continue to shrink, and therefore future growth and social welfare will rely increasingly on knowledge-intensive industries and services, and ever more jobs will require a higher education qualification. Human resources are a core determinant of quality in higher education and research. Universities must therefore work to enhance their human potential, both qualitatively and quantitatively, by attracting, developing and keeping talent in teaching/research careers. Excellence may only emerge from a favourable professional environment based in particular on open, transparent and competitive procedures. Research and development (R&amp;D) has proven to be a crucial factor in shifting the world’s technological frontiers, while at the same time facilitating new technological and scientific innovations. This paper will focus on R&amp;D at the Institute for Nanomaterials, Advanced Technologies and Innovation at the Technical University of Liberec, Czech Republic. After a description of a literary search in the introduction, the specific real situation at this institute is mentioned, i.e. the number of submitted and solved national and international projects, statistics on research and development sources, and of course human resources at the institute. In the conclusion, the reader will be able to get a picture of how to increase the institute competitiveness in international collaboration.</p></abstract>ARTICLE2021-01-29T00:00:00.000+00:00Conditions for Experimental Activities at Elementary and High Schools from Chemistry Teachers’ Point of View<abstract><title style='display:none'>Abstract</title><p>School experiments represent a necessary means of subject-matter presentation in chemistry education and are important for chemical (scientific) thinking. Despite being a focus of several texts, a complex view on the experimental activity in chemistry education in Czechia is missing. The results of a questionnaire survey among 466 lower-secondary, lyceum and grammar school teachers focused on types of conducted experiments, their frequency, the place they are conducted. The most frequently used chemicals and sources of inspiration are presented in the paper. The results show that despite experiments’ significant role in education, its occurrence is rather seldom and teacher’s demonstrations prevail over students’ experiments. The list of the most often used chemicals suggests the experiments are mostly focused on inorganic chemistry. These results open further questions regarding occupational safety at schools as an important factor which could also be the reason for such a low representation of experiments in Czech chemistry education.</p></abstract>ARTICLE2021-01-29T00:00:00.000+00:00Hydrogen - Some Historical Highlights<abstract><title style='display:none'>Abstract</title><p>The early history of experiments in which an inflammable air was prepared is outlined. Once hydrogen had been discovered by Cavendish in 1766, the world of science and technology was given a colossal impetus. Its scientific and social consequences form the main focus of this essay. Special attention is given to explain why experiments were done, and their aims. The many difficulties which confronted scientists in the interpretation of their results are discussed. Timelines have been used in order to facilitate an understanding of the evolution of ideas. A particular emphasis is given to the story of how, through spectral analysis of the hydrogen atom, our understanding of atomic structure developed. Experiments involving hydrogen constitute important teaching material in schools. Detailed instructions are given for making hydrogen in the laboratory and for demonstrating its lightness and flammability. Suggestions are made of how to use these reactions to teach a wide variety of chemical concepts and facts.</p></abstract>ARTICLE2021-01-29T00:00:00.000+00:00Basic Multivariate Statistical Methods for Environmental Monitoring Data Mining: Introductory Course for Master Students<abstract><title style='display:none'>Abstract</title><p>The present introductory course of lectures summarizes the principles and algorithms of several widely used multivariate statistical methods: cluster analysis, principal components analysis, principal components regression, N-way principal components analysis, partial least squares regression and self-organizing maps with respect to their possible application in intelligent analysis, classification, modelling and interpretation to environmental monitoring data. The target group of possible users is master program students (environmental chemistry, analytical chemistry, environmental modelling and risk assessment etc.).</p></abstract>ARTICLE2021-01-29T00:00:00.000+00:00Current Trends in Recycling of Photovoltaic Solar Cells and Modules Waste / Recykling Zużytych Ogniw I Modułów Fotowoltaicznych - Stan Obecny<abstract><title style='display:none'>Abstract</title><p>In comparison to other energy producing techniques, photovoltaics (PV) is one of the most promising options: no emission of any matter into the environment during operation; extremely long operation period (estimated average: 25 years), minimum maintenance, robust technique, aesthetic aspects. The use of photovoltaics is rapidly increasing, and the respective market is developing accordingly. Although PV manufacturing equipment is now excluded from the scope of RoHS, according to the Kyoto Protocol and the EU Directives WEEE and RoHS the use of hazardous substances in electric/electronic devices has to be reduced stepwise to approximately zero level. Furthermore, a total recycling of nearly all materials involved is aimed. Thus, major attention is directed to avoidance of environmental pollution through combustion or landfill, to regain valuable material, to promote the development and use of renewable energy sources. As the lifetime of PV cells themselves is much longer than that of PV modules and the manufacturing process of cells requires much energy consumption, the reuse of base material of the cells is economically justified. The aim of this work was to develop and evaluate existing methods of PV cells and modules recycling. The article discusses the main outcomes and analyses the significance of recycling in relation to the environmental profile of the production and total life cycle of photovoltaic cells and modules</p></abstract>ARTICLE2013-01-17T00:00:00.000+00:00Pregradual Preparation of Teachers in Slovakia / Etapy Przygotowania Nauczycieli Do Zawodu Na Słowacji<abstract><title style='display:none'>Abstract</title><p>The contribution deals with the quality of pregradual preparation of teachers in the Slovak Republic. It analysis the causes of continuously decreasing number of secondary school graduates interested in teaching profession. The contribution evaluates present situation in pregradual preparation of teachers regarding the proportion of professional, pedagogical and psychological and didactic part. As far as the didactic part is concerned, the contribution points out the need for new approaches to be applied supporting digital technologies.</p></abstract>ARTICLE2013-01-17T00:00:00.000+00:00Functional Dependence Between Expectancy of People’S Life and Mankind Population During the Time of Demographic Transition / Funkcjonalna Zależność Trwałości Życia Ludzi Od Liczebności Ludzkości Świata W Okresie Przejścia Demograficznego<abstract><title style='display:none'>Abstract</title><p>In this work is an attempt to mathematically prove the existence of the demographic transition taking into account one of its features, such as extension of human life dependent on the growth of the human population. Determined the functional form of this dependence, and the relationship between the probability of death, life expectancy, and social involving in the states of T (the influence of “traditional” values of concepts) and R (in the range of rules and possibilities of modern civilization).</p></abstract>ARTICLE2013-01-17T00:00:00.000+00:00Teaching Experimental Chemistry in English Schools / Nauczanie Chemii Doświadczalnej W Angielskich Szkołach<abstract><title style='display:none'>Abstract</title><p>An historical background to the teaching of chemistry is presented, together with examples of great teachers from the past. Some aspects of the modern English school chemistry syllabus are discussed, both from the point of view of its theoretical content and its aim in helping children to develop practical skills. Chemistry Clubs, Open days and popular science lectures are also mentioned as a means of stimulating interest in chemistry as taught in schools.</p></abstract>ARTICLE2013-01-17T00:00:00.000+00:00Determination of Degradation Products of Plant Origin Pigments in the Bottom Sediments of Lakes / Oznaczanie Zawartości Produktów Degradacji Barwników Pochodzenia Roślinnego W Osadach Dennych Jezior<abstract><title style='display:none'>Abstract</title><p>The objective of this exercise was to introduce students to one of the methods used for determination of the content of pigments’ degradation products in lake bottom sediments characterised by heterogeneous physical and chemical properties. The research revealed that the studied bottom sediments were characterised by diverse content of products produced during degradation of pigments of plant origin, whereas higher concentrations of these compounds were found in sediments containing inorganic carbon (carbonates). The obtained results also indicate that it is important to have the results properly presented, particularly in the case of samples containing the carbonates.</p></abstract>ARTICLE2013-01-17T00:00:00.000+00:00„Good” and „Bad” Ozone - Evaluation on the Basis of Plant Reaction to Ozone / „Dobry” I „Zły” Ozon - Ocena Na Podstawie Reakcji Roślin Na Ozon<abstract><title style='display:none'>Abstract</title><p>Ozone is a natural and artificial chemical compound of Earth’s atmosphere. O3 is an absorbent of ultraviolet and infrared radiation and has strong oxidative properties. In the stratosphere the ozone layer protects the planet’s surface from dangerous UV radiation, its indirect effect on plant organisms is positive so stratospheric ozone can be called “good” ozone. The depletion of the ozone layer, as a result of atmosphere pollution, described as an ozone “hole” is causing UVB radiation enhanced level on Earth’s surface. The genetic, cytological, physiological and morphological reaction of prolonged UVB exposure in plants is twofold: it damages plants and simultaneously plants protect themselves and repair their injuries. The ozone in the troposphere originates from natural sources and is also a secondary pollutant, formed in photochemical reactions, leading to “smog” and ozone “spots” occurrence. As a strong oxidant, O3 is directly toxic to plants and can be recognized as “bad” ozone. Ozone is also classified as a “greenhouse” gas, participating in global warming. It is difficult to value the impact of O3 as a “greenhouse” gas on plants. The combined effect of O3 changes in the stratosphere and troposphere on plants can be estimated as loss in crop yield and in productivity of natural ecosystems</p></abstract>ARTICLE2013-01-17T00:00:00.000+00:00Insecticide and Food Consumption of Spanish Slug (Arion Lusitanicus Mabille 1868) / Insektycydy A Konsumpcja Pokarmu Przez Ślinika Luzytańskiego (Arion Lusitanicus Mabille 1868)<abstract><title style='display:none'>Abstract</title><p>In the years 2007 and 2011, research was carried out on the impact of: pyrethroid group agents (beta-cyfluthrin, lambda-cyhalothrin, deltamethrin, esfenvalerate, alpha-cypermethrin, bifenthrin) benzoylphenyl ureas (teflubenzuron), derivatives of pyridine (pyriproxyfen), organophosphorus (diazinon) and neonicotinoid insecticides (acetamiprid) on the food consumption by Spanish slug (<italic>Arion lusitanicus </italic>Mab). The quantity of food consumed by animals treated by plant protection agents, the quantity of food treated by insecticides consumed and food preferences of <italic>A. lusitanicus </italic>individuals were analysed. The slugs were made available a selection between food with an addition of insecticide and without it. The results obtained indicate that the preparations which contained lambda-cyhalothrin and deltamethrin with which the animals were treated increase the quantity of food consumed by the Spanish slug. It was also shown that the food treated with lambdacyhalothrin and alpha cypermethrin is consumed in a larger amount than the food not treated by this preparation. Deltamethrin and lambda-cyhalothrin and pyriproxyfen probably constitute food attractants for <italic>A. lusitanicus</italic> individuals and also alpha-cypermethrin, bifenthrin, beta-cyfluthrin and esfenvalerate are additive, which reduces the attractiveness of food for slug.</p></abstract>ARTICLE2013-01-17T00:00:00.000+00:00Computerized Adaptive Testing in Poland / Komputerowe Testowanie Adaptacyjne W Polsce<abstract><title style='display:none'>Abstract</title><p>New trends relating to computer-based testing of learners’ achievements are presented in the paper. It describes adaptive testing methods and results of studies in this problem area. Essential questions connected with the Item Response Theory (IRT) were also discussed. The presented data indicate that computer-based adaptive testing should be popularized in Poland to its fullest extent.</p></abstract>ARTICLE2013-01-17T00:00:00.000+00:00Changes in Water Chemistry as a Result of Rainfall Runoff from the Roofs of Various Coatings. Part I / Kształtowanie Się Chemizmu Wód Opadowych W Wyniku Spływu Z Dachów O Różnych Pokryciach. Część I<abstract><title style='display:none'>Abstract</title><p>The aim of the study was to determine the level of calcium, magnesium, sodium, phosphorus and potassium in the waters flowing from the roofs of houses with varying degrees of coverage on the background of their contents in rain waters. On the basis of the Minister of Environment Decree of 24 July 2006 on conditions to be met for the introduction of sewage into the water or ground and on substances particularly harmful to the aquatic environment, runoff from paved areas shall be treated as sewage, and runoff from roofs of buildings are treated as pure water and can be discharged into the environment without a permit. However, literature data indicate the possibility of a significant enrichment of rainwater at the time of contact with the roof covering. The study included 24 roofs of houses or small trade buildings. As background to the research used rainwater collected in two randomly selected locations within the area of research. The study was conducted in areas with low human impact, in order to best capture the effect of the type of roofing material on the formation of water chemistry. Research area was located in the Luslawice in the Tarnow county in Malopolska province. The study included the most common roofs in the surveyed area: cement tile, ceramic tile, bituminous, unpainted galvanized metal, copper and asbestos cement. The tested water samples to determine the content of calcium, phosphorus, magnesium, sodium and potassium. In addition, it was determined the pH value of water and electrolytic conductivity. The results of this study indicate that the water runs off the roofs of respondents in each case contained a greater quantity of the analyzed elements in comparison with rainwater. For example, while the average content of magnesium in the water flowing from the tile cement was almost ten times higher than in rain water, in the case of tile ceramic was almost five times more water from the bituminous coverings contained about three times more magnesium, and water from the galvanized metal contained about six times more as compared with rainwater. Also in the case of most other elements enrichment factors found in the waters cover the cement (tile, and asbestos cement) then galvanized and coated while the lowest were recorded in the enrichment of waters from the roofs of the covering of ceramic tiles. Also noted an increase in the conductivity values in waters from the roofs of the coverings of cement, galvanized steel and ceramic tiles. All runoff from the roofs were of generally higher pH value compared with rainwater, the biggest reaction - about 8 found in the water with cement tiles, slightly lower, about 7.0 in water from roofs with ceramic tiles and sheet copper. pH of the water in the coated sheet was lower than in water, rainwater and oscillating within 5.5. Rainwater pH was 5.94.</p></abstract>ARTICLE2013-01-17T00:00:00.000+00:00Pollution of the Ecosystem of the Rusalka City Lake with Heavy Metals / Zanieczyszczenie Ekosystemu Śródmiejskiego Jeziora Rusałka Metalami Ciężkimi<abstract><title style='display:none'>Abstract</title><p>In the vegetation season April-October 2010, the value of and the changes in Zntot., Cutot., Cdtot. and Pbtot. concentrations in the water of the Rusalka flow-through lake (with average water retention of ca 30 days) situated in the city centre of Szczecin were determined. Water temperature, pH, concentration of dissolved oxygen (with calculation of water saturation with O2), COD-Cr and BOD5, total hardness, - 3 HCO concentration (as total alkalinity), Cl-, - 24 SO , Mntot and Fetot were also determined. The data collected may be used to evaluate the ecological and chemical status of the surface waters under investigation. As far as the ecological status of the Rusalka Lake is concerned, the investigated waters were found, based on the official criteria being in force in Poland in evaluation of the ecological and chemical status of surface waters, to conform to water quality classes I and II considering total zinc and copper concentrations, temperature and dissolved oxygen concentration (except water inflow to the lake in August) as well as BOD5, - 24 SO and Cl- concentrations and pH value; however, they were always worse than water quality class II while taking the COD-Cr values into account. Regarding the chemical status of the investigated waters, total cadmium and lead concentrations were the levels exceeding the admissible values according to the official criteria in Poland. Changes in the values of indices being investigated along water flow path allowed stating that the equilibriums between the sedimentation and the resuspension and the dissolution processes during the research period were shifted towards sedimentation in case of Zn and Cd only, as well as of the organic matter sedimenting in the form of divalent cation- and divalent anion-sorbing gels. Although three phytoplankton blooms occurred in the body of water, unfortunately weak ones, the dissimilation processes prevailed over assimilation.</p></abstract>ARTICLE2013-01-17T00:00:00.000+00:00en-us-1