Teaching Patterns of Scientific Inquiry: A Video Study of Chemistry Lessons in Germany and Sweden

Despite the central role of Scientific Inquiry within science education, this topic is rarely focused upon during science lessons in Germany. A comparison with a school system that emphasises Scientific Inquiry in a stronger way (such as the Swedish system) would enable the identification of culturespecific teaching patterns in terms of the instruction of Scientific Inquiry. For this reason, such a comparison has been made within this study. This study has been undertaken as a low- and middle-inferent video analysis. The study provides information concerning culture-specific teaching patterns in Germany and Sweden on the level of general (organisational) teaching processes and of the phases of Scientific Inquiry. The study was carried out with ten German und nine Swedish video-recorded chemistry lessons. The results, presented in this paper, show that German chemistry lessons are organised in a more product-oriented way than the Swedish chemistry lessons.Peer Reviewe

DEVELOPMENT OF A FLAT-SURFACE TEST STAND FOR INVESTIGATIONS ON DRIVING DYNAMICS

Road-test research on braking dynamics led to the knowledge of global and local system behaviour and to the wish to investigate local effects under defined and repeatable, but still real conditions. To meet all these requirements the quarter-car flat-surface test stand 'EFA' with the ability to simulate vehicle dynamics of a quarter-car three-dimensionally was developed and built by the Institute of Automotive Engineering (f z d) of the Technical University of Darmstadt (THD). Based on the principle of kinematic inversion a flexible power-drive belt made of polyamide coated with elastomer simulates the moving road surface with a μ-slip characteristic like dry asphalt up to a maximum speed of 100 km/h. Realistic vertical excitation of the quarter-car with real suspension, body mass and ABS is possible by moving the wheel support under the belt with frequencies up to 2.5 Hz and amplitudes up to 40 mm. This concept enables to measure dynamic wheel load up to 15.000 N directly in the road. The research work presented here shows the necessity and advantage of a fiat-surface test stand for investigations on braking dynamics under real conditions and describes the concept for these investigations for the future

Replacement of connexin43 by connexin26 in transgenic mice leads to dysfunctional reproductive organs and slowed ventricular conduction in the heart

BACKGROUND: In order to further distinguish unique from general functions of connexin43, we have generated mice in which the coding region of connexin43 was replaced by that of connexin26. RESULTS: Heterozygous mothers showed impaired mammary gland development responsible for decreased lactation and early postnatal death of the pups which could be partially rescued by wild type foster mothers. Only about 17% of the homozygous connexin43 knock-in connexin26 mice instead of 25% expected according to Mendelian inheritance, were born and only 6% survived to day 21 post partum and longer. Neonatal and adult connexin43 knock-in connexin26 mice exhibited slowed ventricular conduction in their hearts, i.e. similar but delayed electrophysiological abnormalities as connexin43 deficient mice. Furthermore, connexin43 knock-in connexin26 male and female mice were infertile and exhibited hypotrophic gonads. In testes, tubuli seminiferi were developed and spermatogonia as well as some primary spermatocytes were present, but further differentiated stages of spermatogenesis were absent. Ovaries of female connexin43 knock-in connexin26 mice revealed only few follicles and the maturation of follicles was completely impaired. CONCLUSION: The impaired gametogenesis of homozygous males and females can explain their infertility

Оптимізація паралельного ітераційного процесу для лінійних систем з розрідженими матрицями

Розглядається один із підходів до побудови передобумовлювача для методу спряжених градієнтів розв'язування СЛАР з розрідженими матрицями нерегулярної структури. Запропоновано та досліджено передобумовлювачі на основі методу паралельних перерізів.Рассматривается один из подходов к построению предобуславливателя для метода сопряженных градиентов решения СЛАУ с разреженными матрицами нерегулярной структуры. Предложены и исследованы предобуславливатели на основе метода параллельных сечений.Considered is one of approaches for construction a preconditioner for method of conjunctive gradients for solution SLAE with sparse matrices of irregular structure. Preconditioners, which are based on method of parallel section, is proposed and investigated

Chemistry Student Teachers’ Scientific Inquiry Competencies

We constructed paper-and-pencil test-items to assess chemistry student teachers’ scientific inquiry competencies. We focused on the inquiry method experiment, divided into three reasoning steps (question & hypothesis; planning & performing; analysis & reflection). Test revision resulted in a test of 20 items, which was applied to a sample of undergraduate and graduate chemistry student teachers. The first explorative assessment (N = 89) based on that instrument (1) revealed acceptable item characteristics, such as an appropriate range of item difficulties (.48 < Pi < .84) and only slightly unsatisfactory item discrimination parameters (.19 < rit < .65). The study (2) obtained preliminary information on the high prognostic potential of the planned degree.Peer Reviewe

Covariates of complex problem solving competency in chemistry

The ability to solve complex and real-life problems is one of the key competencies in science education. Different studies analyzed the relationships between complex problem solving (CPS) and covariates such as intelligence, prior knowledge, and motivational constructs on a manifest level. Additionally, research findings indicate that intelligence and prior knowledge are substantial predictors of CPS. Due to the interconnections between covariates, the relationships between CPS and covariates are quite complex. Therefore, we propose a model which describes these relations by taking direct and indirect effects into account. All analyses are based on structural equation modeling. Results show that the proposed model represents the data with substantial goodness-of-fit statistics and explanation of variance. Intelligence, domain-specific prior knowledge, computer familiarity, and attendance in advanced chemistry courses are direct predictors of CPS, while interest and scientific self-concept show indirect effects.Peer Reviewe

Developing a computer-based assessment of complex problem solving in Chemistry

Background Complex problem-solving competence is regarded as a key construct in science education. But due to the necessity of using interactive and intransparent assessment procedures, appropriate measures of the construct are rare. This paper consequently presents the development and validation of a computer-based problem-solving environment, which can be used to assess students' performance on complex problems in Chemistry. The test consists of four scales, namely, understanding and characterizing the problem, representing the problem, solving the problem, and reflecting and communicating the solution. Based on this four-dimensional framework, the computer-based assessment has been evaluated with the data of N = 395 10th grade high school students. Results Result showed that students' complex problem-solving competence could be modelled by four related but empirically distinct factors with moderate to high intercorrelations. The construct showed substantial relations with fluid intelligence and prior domain knowledge in Chemistry, indicating that construct validity and domain specificity were given. Processes of understanding and characterizing the problem were substantially related to subsequent processes in complex problem solving. Conclusions Due to the complexity of complex problem-solving processes in Chemistry, multidimensionality of the construct could be assumed. Consequently, science educators should take into account abilities of understanding, representing, solving the problem, and finally reflecting and communicating the solution when developing instructional approaches and valid computer-based assessments