The Physics Educator

This brief article is directed towards young readers, perhaps in their teens, who might be thinking about their future careers and the paths that they might like to follow in later life. I give them for consideration an outline of the fun and excitement that I have myself experienced in scientific research, and encourage them to follow me. To do this, I start by giving some remarks about my own early life and its choices. I then identify some of the decisions and lucky breaks that led to my main scientific work on the theories of stability, nonlinear dynamics and chaos. I point to some new frontiers where knowledge of the physical sciences is spreading into wider areas such as the bio-mechanics of DNA and the prediction of tipping points that could dramatically increase global warming. Finally I give some detailed advice that could be useful as you hopefully enter the thrilling world of scientific research.

In the topics of mechanics, readily available instruments such as the Force Concept Inventory (FCI) and the Mechanics Baseline Test (MBT) have been extensively used to assess students’ conceptual understanding, especially for high school and undergraduate students. In this paper, the relevancy of these two instruments in excerpting conceptual understanding of high-performing students was examined and the results were elaborated. The findings in this paper suggest that the FCI and MBT are indeed effective to show students’ basic conceptual understanding in mechanics but should not be used to assess improvement after learning intervention or to differentiate students’ conceptual understanding in a population of high performers. More advanced assessments, such as those that comprise higher order thinking questions, should be used for such purposes.

In relativistic dynamics, the direction of acceleration is not generally parallel to the direction of force. Both the magnitude and direction of an object’s three-acceleration can alter even when the magnitude of the applied three-force is constant. Graphs of the variation in acceleration and the angles between an object’s velocity, acceleration, and the applied force vectors are presented in order to illustrate the behavior at close to the speed of light.

We explore the load current $I_{M\times N}$ for a rectangular array (matrix) of $MN$ identical cells where $N$ strings (columns) of $M$ serial cells (rows) are arrayed in parallel. $I_{M\times N}$ is equal to $I_{N\times M}$ with the internal resistance of the cell and the load resistance exchanged. By treating a linear fractional function as a translated inversely-proportional function, we can easily capture the properties of $I_{M\times N}$ and the relative magnitude of $I_{M\times N}$ and $I_{N\times M}$ via their ratio. The limiting behaviors of the load current are discussed beyond the ideal-cell and short-circuit limits. For the given total number of cells, we graphically verify the recent findings on the matrix of cells that produces the maximum load current. Finally, we analyze the possibility of a car starting with lemon cells or AA dry cells in matrix. This work would be useful in creating a high school or university curriculum that unifies identical cells in series, parallel, or matrix.

In this paper, the main concepts and the preliminary results related to a new approach for creating innovative green laboratory experiences in applied science and technology will be discussed. The term ebatronics is here introduced for the first time in the literature to indicate a kind of experimental laboratory based on the conjunction of wooden recycled materials and microcontroller based devices. In particular, tensegrity based systems are presented. A gallery of prototypes developed by the authors is shown. An intense set of photos will illustrate the real effectiveness of the proposed laboratory project.