Teaching science and technology at primary school level: theoretical and practical considerations for primary school teachers' professional training.

This paper focuses on the importance of starting science and technology education at a young age and at the consequential importance of providing primary school teachers with enough professional background to be able to effectively incorporate science and technology into their teaching. We will discuss a large-scale program in The Netherlands that is aimed at the professionalization of elementary school teachers in the field of science and technology. Theoretical and practical considerations will be provided for the three pillars that ideally should be included in teacher training programs in this domain: (1) Primary school teachers’ knowledge of and competency in scientific concepts and scientific reasoning; (2) Primary school teachers’ attitude towards science (in terms of cognitive, affective, and behavioural dimensions of attitude); and (3) Primary school teachers’ pedagogical competency to enhance inquiry-based learning

Measurement of Turbulence Power Spectra in Agitated Vessels of Different Size with a Laser-Doppler Velocimeter

We have used the laser-Doppler velocimeter with a new noise reduction technique for measurements in water-filled, turbine-agitated vessels of several sizes, but of the same geometry. Mean velocities, turbulence intensities and turbulence power spectra were obtained in the impeller stream region. With these results we hope, in the future, to put scaling rules for mixing vessels on a sounder basis

Effects of company visits on Dutch primary school children's attitudes toward technical professions

Technology-oriented company visits could potentially provide children with a stimulating ‘real-world’ setting to develop more broad and positive images of and attitudes toward technology and technical professions. The present study was the first to explore whether children’s images of and attitudes toward technology, technical competencies and technical professions could be affected by technology-oriented company visits, as they are presently carried out in the Netherlands. A previously validated measurement instrument was used to measure children’s images and attitudes prior to and after the visits and results were compared to similar measurements among children who did not take part in the visits. In addition, based on recent review studies about school visits to science centers, we derived several key theoretical guidelines for organizing effective school visits. Based on these guidelines, structured interviews were carried out with all teachers prior to the company visits. Results indicated that children’s images and attitudes remained mostly unaffected by the company visits, a finding that could be explained by the fact that the level of in-school preparation, follow-up activities and teachers’ level of involvement during the visits was generally low. In addition, observations during the visits showed that the activities at the technical companies were mostly ‘hands-on’ and stereotypical (e.g., working with machines). Based on these findings, we formulate a set of new guidelines for technology-oriented company visits that could improve the desired attitudinal effects

Bistable hysteresis and resistance switching in hydrogen gold junctions

Current-voltage characteristics of H2-Au molecular junctions exhibit intriguing steps around a characteristic voltage of 40 mV. Surprisingly, we find that a hysteresis is connected to these steps with a typical time scale > 10 ms. This time constant scales linearly with the power dissipated in the junction beyond an ofset power P_s = IV_s. We propose that the hysteresis is related to vibrational heating of both the molecule in the junction and a set of surrounding hydrogen molecules. Remarkably, we can engineer our junctions such that the hysteresis' characteristic time becomes >days. We demonstrate that reliable switchable devices can be built from such junctions.Comment: Submitted to Phys. Rev. Let

Numerical modelling of physical processes governing larval transport in the southern North Sea

A three-dimensional hydrodynamic model (GETM) was coupled with a particle tracking routine (GITM) to study the inter-annual variability in transport paths of particles in the North Sea and English Channel. For validation, a comparison with observed drifter trajectories is also presented here. This research investigated to what extent variability in the hydrodynamic conditions alone (reflecting passive particle transport) contributed to inter-annual variability in the transport of eggs and larvae. In this idealised study, no a priori selection of specific spawning grounds or periods was made and no active behaviour (vertical migration) or mortality was included. In this study, egg and larval development towards coastal nursery areas was based solely on sea water temperature, while settlement areas were defined by a threshold water depth. Results showed strong inter-annual variability in drift direction and distance, caused by a combination of wind speed and direction. Strong inter-annual variability was observed both in absolute amount of settlement in several coastal areas, and in the relative importance of the different areas. The effects of wind and temperature variability are minor for settlement along the western shores of the North Sea and in the English Channel, but have a very significant impact on settlement along the eastern shores of the North Sea. Years with strong south-westerly winds across the Dover Straight resulted in higher settlement figures along its eastern shores of the North Sea (standard deviation 37% of the mean annual settlement value). Settlement in the western Dutch Wadden Sea did not only show inter-annual variability, but patterns were also variable within each year and revealed seasonal changes in the origin of particles: during winter, stronger currents along with colder temperatures generally result in particles originating from further away

Measuring primary school teachers’ attitudes towards new technology use: development and validation of the TANT questionnaire

This study concerns the development and validation of a questionnaire to measure primary school Teachers’ Attitudes towards New Technology use in teaching (TANT). Many researchers, policy makers and educators have emphasized the importance of using new technology in teaching. However, no instrument is available to measure teachers’ attitudes towards using new technology in teaching. In a previous literature study (authors), we used the well-known Theory of Planned Behaviour to identify and structure eight underlying factors that make up primary school teachers’ attitudes towards using technology in teaching. In the current study we aim to measure these factors. To that end, we developed eight corresponding scales, as well as a scale to measure primary school teachers’ use of new technology. Results of the validation study among 659 pre- and in-service teachers showed adequate convergent and discriminant validity for six attitudinal factors and teachers’ use of new technology. In addition, we explored the predictive validity of the attitudinal factors for explaining variability in teachers’ use of new technology and established configural, metric and scalar measurement invariance

Bulk and Surface Nucleation Processes in Ag2S Conductance Switches

We studied metallic Ag formation inside and on the surface of Ag2S thin films, induced by the electric field created with a STM tip. Two clear regimes were observed: cluster formation on the surface at low bias voltages, and full conductance switching at higher bias voltages (V > 70mV). The bias voltage at which this transition is observed is in agreement with the known threshold voltage for conductance switching at room temperature. We propose a model for the cluster formation at low bias voltage. Scaling of the measured data with the proposed model indicates that the process takes place near steady state, but depends on the STM tip geometry. The growth of the clusters is confirmed by tip retraction measurements and topography scans. This study provides improved understanding of the physical mechanisms that drive conductance switching in solid electrolyte memristive devices.Comment: In press for PR