II: The Conflict

An environmental project in a native language German class (writing a book on environmental issues) gave the pupils, thirteen‐yea‐old girls, a large scope of freedom for independent group work. When they could not present sufficient results of their work at an interim report stage, a serious conflict resulted in which the teacher reproached the pupils heavily. In the case study this conflict is analysed: its possible causes, processes and some of its effects. Available data were the teacher's own diary and essays in which the pupils wrote frankly how they experienced the conflict. One issue arising from the analysis was the differences between the teacher"s intentions (e.g. to stimulate self‐determination in the pupils) and what he had achieved In this conflict (e.g. showing them how narrow their room for discretion actually was). Another issue was the pupils” sense of responsibility for the project (e.g. the pupils saw the project as the teacher's business and not as their project). One of the hypotheses that emerged to explain the apparent inactivity of the pupils was their perception of “work”, which seemed to have been incompatible with a largely self‐determined activity. The study ends with the teacher's reflections on what he gained from the analysis. One outcome was an involuntary caution in the use of words in his interactions with pupils and a more intense feeling of respect for them as young personalities. Another was a reconstruction of his strategic approach to the design of project work.     

Differentiation and social selectivity in German higher education

In this paper we investigate social selectivity in access to higher education in Germany and, unlike most previous studies, explicitly devote attention to semi-tertiary institutions such as the so-called universities of cooperative education. Drawing on rational choice models of educational decisions we seek to understand which factors influence upper secondary graduates from different social backgrounds in their choices of diverse tertiary institutions in Germany. We find that scholastic performance, expected job security, study duration, monetary costs and preferences for study content considerably contribute to the creation of socially selective choice patterns of post-secondary careers. The characteristics of semi-tertiary institutions—such as universities of cooperative education that combine firm-based training with tertiary education—constitute a potential alternative that could reduce inequities in access to higher learning.     

Extracting the hydrodynamic resistance of droplets from their behavior in microchannel networks

The overall traffic of droplets in a network of microfluidic channels is strongly influenced by the liquid properties of the moving droplets. In particular, the effective hydrodynamic resistance of individual droplets plays a key role in their global behavior. Here we propose two simple and low-cost experimental methods for measuring this parameter by analyzing the dynamics of a regular sequence of droplets injected into an “asymmetric loop” network. The choice of a droplet taking either route through the loop is influenced by the presence of previous droplets that modulate the hydrodynamic resistance of the branches they are sitting in. We propose to extract the effective resistance of a droplet from easily observable time series, namely, from the choices the droplets make at junctions and from the interdroplet distances. This becomes possible when utilizing a recently proposed theoretical model based on a number of simplifying assumptions. Here we present several sets of measurements of the hydrodynamic resistance of droplets, expressed in terms of a “resistance length.” The aim is twofold: (1) to reveal its dependence on a number of parameters, such as the viscosity, the volume of droplets, their velocity as well as the spacing between them. At the same time (2), by using a standard measurement technique, we compare the limitations of the proposed methods. As an important result of this comparison, we obtain the range of validity of the simplifying assumptions made in the theoretical model.