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Although demonstrations play a central role in teaching and learning chemistry, the effects of concrete setup principles have rarely been subject to systematic empirical studies. According to the left-to-right principle, the educator should begin with the first step of a reaction in the upper left part of the setup and then place the following apparatus in the lower right. Using data from an experimental eye-tracking study on students' visual attention that was published in the "Journal of Chemical Education," we reanalyzed eye-tracking in order to find out whether eye-movements are influenced in a manner that supports a setup according to the left-to-right principle. On the basis of a pattern analysis, the results show that left-to-right patterns generally appear significantly more often within the data than right-to-left patterns. Although the left-to-right demonstration does not seem to systematically include more left-to-right patterns, it is associated with a decrease of right-to-left patterns. Accordingly, a right-to-left setup seems to add more eye-movements that do not follow the logic of the demonstration. We discuss these findings with regard to their importance for educators and new perspectives on future chemistry demonstrations research.

This edition of the European Conference on Neutron Scattering, which is held every four years, took place in Garching, Germany and gathered over 500 people from all areas of neutron science. From new source or instrumental concepts to fundamental physics, and chemistry, all areas of this community were represented. Lively discussions in the lecture halls, poster areas,and social events around this conference contributed to a very fruitful exchange of new ideas.

Although many chemistry demonstrations are proposed in educational literature, there are hardly any studies on how demonstrations should be set up in order to support students' perception. Against this background, the aim of the present study was to present and test setup principles for chemistry demonstrations, with regards to indicators of students' visual attention on the relevant equipment in a demonstration. On the basis of the Gestalt principles, we carried out an experimental double-blind eye-tracking study. We set up six demonstrations that each corresponded to one Gestalt principle ("Gestalt setting") and six demonstrations that explicitly violated one principle ("control setting"). There were 146 students from secondary schools randomly assigned to watch a demonstration either in a Gestalt or a control setting. Visual attention was captured using an eye-tracker (eye-follower 2.0). The total fixation count, total fixation duration, total mean fixation duration, and time taken to fixate were analyzed. The results show that demonstration setups have an impact on visual attention, with small to medium effects for each Gestalt principle. In order to support learners watching a demonstration, educators should carefully plan the setup with regard to their concrete learning goal(s) and the equipment they want to focus on. In particular cases, educators will have to decide purposefully between competing principles.

The atomistic structure and dynamics obtained from molecular dynamics (MD) simulations with the example of TIP3P (rigid and flexible) and TIP4P/2005 (rigid) water is compared to neutron and X-ray scattering data at ambient conditions. Neutron and X-ray diffractograms are calculated from the simulations for four isotopic substitutions as well as the incoherent intermediate scattering function for neutrons. The resulting curves are compared to each other and to published experimental data. Differences between simulated and measured intermediate scattering functions are quantified by fitting an analytic model to the computed values. The sensitivity of the scattering curves to the parameters of the MD simulations is demonstrated on the example of two parameters, bond length and angle.

In this work, we use ab initio molecular dynamics simulations to elucidate the electronic properties of three hydrated zwitterionic amino acids, namely proline, hydroxyproline, and alanine, the former two forming an important constituent of collagen. In all three systems, we find a substantial amount of charge transfer between the amino acids and surrounding solvent, which, rather surprisingly, also involves the reorganization of electron density near the hydrophobic non-polar groups. Water around proline appears to be slightly more polarized, as reflected by the enhanced water dipole moment in its hydration shell. This observation is also complemented by an examination of the IR spectra of the three systems where there is a subtle red and blue shift in the O–H stretch and bend regions, respectively, for proline. We show that polarizability of these amino acids as revealed by a dipole moment analysis involves a significant enhancement from the solvent and that this also involves non-polar groups. Our results suggest that quantum mechanical effects are likely to be important in understanding the coupling between biomolecules and water in general and in hydrophobic interactions. [ABSTRACT FROM AUTHOR]