Physical versus virtual manipulative experimentation in physics learning

The aim of this study was to investigate whether physical or virtual manipulative experimentation can differentiate physics learning. There were four experimental conditions, namely Physical Manipulative Experimentation (PME), Virtual Manipulative Experimentation (VME), and two sequential combinations of PME and VME, as well as a control condition (i.e., traditional instruction with absence of PME or VME). Undergraduate students' understanding of physics concepts in the domain of heat and temperature was tested in a pre- and posttest design that involved 182 participants assigned to the four experimental groups and 52 participants assigned to the control group. Conceptual tests were administered to assess students' understanding before, during and after instruction. The analyses revealed that the four experimental conditions were equally effective in promoting students' understanding of concepts in the domain of heat and temperature and better than the control condition; hence, manipulation, either physical or virtual manipulation, and not physicality, as such, at least in a context like the one of the present study, is important in physics learning

Blending physical and virtual manipulatives: An effort to improve students' conceptual understanding through science laboratory experimentation

This study aimed to investigate the effect of experimenting with physical manipulatives (PM), virtual manipulatives (VM), and a blended combination of PM and VM on undergraduate students' understanding of concepts in the domain of Light and Color. A pre-post comparison study design was used for the purposes of this study that involved 70 participants assigned to three conditions. The first condition consisted of 23 students that used PM, the second condition consisted of 23 students that used VM, and the third condition consisted of 24 students that used the blended combination of PM and VM. In the case of the blended combination, the use of VM or PM was selected based on whether it provides an affordance that the other medium of experimentation (PM or VM) cannot provide. All conditions used the same inquiry-oriented curriculum materials and procedures. Conceptual tests were administered to assess students' understanding before, during, and after teaching. Results revealed that the use of a blended combination of PM and VM enhanced students' conceptual understanding in the domain of Light and Color more than the use of PM or VM alone

Industrial nox control via h2-scr on a novel supported-pt nanocatalyst

We describe here the performance of a novel MgO-CeO2-supported Pt nanocatalyst (∼1.5nm mean Pt particle size) towards the selective conversion of NO (XNO>90%) into N2 (SN2>80%) using H2 (H2-SCR) in the low-temperature range of 120-180°C for a wide range of O2, H2 and CO2 feed concentrations. This catalytic system showed remarkable performance under industrial process conditions of NOx control [1-5]. Using a feed composition containing 150ppm NO, 2vol% O2 and H2 in the 0.2-0.8vol% range (GHSV=33,000h-1), the NO conversion, XNO (%) and N2-selectivity, SN2 (%) were found to increase with increasing H2 feed concentration in the 120-180°C range, where NO conversions in the 97-100% range and N2-selectivities in the 83-93% range were obtained. By increasing the O2 feed concentration from zero to 5vol%, both the XNO (%) and the SN2 (%) were found to decrease by an extent which was dependent of reaction temperature. The effect of CO2 in the feed stream (0-12vol%) was found to be slightly negative for the NO conversion, while an opposite behavior was found for the SN2 (%), likely due to competitive adsorption of CO2 and NO on the same non-selective NOx adsorption sites. In situ DRIFTS studies have shown that the oxygen feed concentration largely influenced the surface concentration of inactive NOx and only slightly that of active NOx intermediates of H2-SCR but not their chemical structure