The Use of Dramatic Demonstrations to Enhance the Motivation and Learning of Chemistry Students

As part of the Virginia Collaborative for Excellence in the Preparation of Teachers (VCEPT) project, a series of demonstrations was incorporated into Chemistry 100: Man and Environment, a science course taken by non-science majors including many prospective K-12 teachers. Dramatic chemical demonstrations were first presented to the undergraduate students by the instructor, and then they used demonstration activities to teach each other during the semester. Finally, these undergraduates presented to the K-6 students in the Norfolk Statue University (NSU) Summer Children’s College. The perceptions of science by the undergraduates at the beginning and end of the course were assessed using a questionnaire. The responses of the K-6 students in the Children’s College were assessed through informal interviews and audience response. The use of these demonstrations seemed to change the perception of science held by the undergraduate students. In addition, this limited assessment indicated that these demonstrations may have helped more of the undergraduates consider teaching as a career option

An equations-of-motion approach to quantum mechanics: application to a model phase transition

We present a generalized equations-of-motion method that efficiently calculates energy spectra and matrix elements for algebraic models. The method is applied to a 5-dimensional quartic oscillator that exhibits a quantum phase transition between vibrational and rotational phases. For certain parameters, 10 by 10 matrices give better results than obtained by diagonalising 1000 by 1000 matrices.Comment: 4 pages, 1 figur

Quasi dynamical symmetry in an interacting boson model phase transition

The oft-observed persistence of symmetry properties in the face of strong symmetry-breaking interactions is examined in the SO(5)-invariant interacting boson model. This model exhibits a transition between two phases associated with U(5) and O(6) symmetries, respectively, as the value of a control parameter progresses from 0 to 1. The remarkable fact is that, for intermediate values of the control parameter, the model states exhibit the characteristics of its closest symmetry limit for all but a relatively narrow transition region that becomes progressively narrower as the particle number of the model increases. This phenomenon is explained in terms of quasi-dynamical symmetry.Comment: 4 figure

Scalable photonic quantum computation through cavity-assisted interaction

We propose a scheme for scalable photonic quantum computation based on cavity assisted interaction between single-photon pulses. The prototypical quantum controlled phase-flip gate between the single-photon pulses is achieved by successively reflecting them from an optical cavity with a single-trapped atom. Our proposed protocol is shown to be robust to practical nose and experimental imperfections in current cavity-QED setups.Comment: 5 pages, 2 figure

Thermoelastic analysis of solar cell arrays and their material properties

Announced report discusses experimental test program in which five different solar cell array designs were evaluated by subjecting them to 60 thermal cycles from minus 190 deg to 0.0 deg. Results indicate that solder-coated cells combined with Kovar n-interconnectors and p-interconnectors are more durable under thermal loading than other configurations

A scale-model room as a practical teaching experiment

A practical experiment is described which was used to help university students increase their understanding of the effect of construction methods and window design on passive solar heating and electrical heating. A number of one tenth scale model rooms were constructed by students and sited out-of-doors in the late autumn. The models were fabricated to mimic available commercial construction techniques with careful consideration being given to window size and placement for solar access. Each model had a thermostatically controlled electric heating element. The temperatures and electricity use of the models were recorded using data-loggers over a two week period. The performances of the models based on energy consumption and internal temperature were compared with each other and with predictions based upon thermal mass and R-values. Examples of questions used by students to facilitate this process are included. The effect of scaling on thermal properties was analysed using Buckingham&rsquo;s p-theorem.<br /