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The present study describes the development and field testing of a simple apparatus-based diagnostic instrument (SABDI) that examines undergraduate students' understanding of the underlying physics principles that explain how simple acoustic apparatuses work. SABDI comprises 13 items. Based on previous research studies and the history of science, the 38 distractors of SABDI were designed to reflect the following four categories of possible misconceptions: (a) direct and (b) incorrect emergent views of sound; (c) explanations based on a device's salient feature; and (d) wrong applications of physics knowledge. Field testing carried out on 159 participants showed the salient features category to be the most popular. SABDI is a valid and reliable tool that could be used to determine students' thinking regarding acoustic devices.

In the present theoretical study, we introduce the entropy concept into Chi's ontological shift theory. Chi distinguishes between two categories of process phenomena, direct and emergent, and claims that incorrectly considering emergent processes as direct ones is one of the sources of students' robust scientific misconceptions. The present study aims to address the needs of high school and undergraduate physics, chemistry, and engineering students being already familiar with the basics of mechanics and the kinetic molecular theory. Acknowledging the contribution of the ontological shift category theory to improving the learning of science, the present paper aims at taking this theory one step further. We argue that more information about scientific phenomena could be gained if we view direct and emergent phenomena as edges of the same scale level of emergency. We show that entropy can be used to evaluate the level of emergency of physical processes. We believe that interpreting scientific phenomena in terms of level of emergency and entropy might promote students' understanding about the underlying mechanisms explaining these phenomena, as well as about the concept of entropy itself. We provide two pedagogical examples of teaching heat and sound using the level of emergency scale and the entropy concept. We demonstrate analytically in these terms: (a) the development of the heat flow rate equation; and (b) the adiabatic nature of the sound propagation process.

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In the present paper we suggest an original physical explanatory model that explains the mechanism of the sound amplification process in a stethoscope. We discuss the amplification of a single pulse, a continuous wave of certain frequency, and finally we address the resonant frequencies. It is our belief that this model may provide students with opportunities to not only better understand the amplification mechanism of a stethoscope, but also to strengthen their understanding of sound, pressure, waves, resonance modes, etc.

Often, a radar measures targets by their distance, or range, from the radar. A method for viewing these measurements is a Range Time plot, which plots the ranges of targets vs. time. When radar tracks objects whose Range Time tracks cross, it is sometimes uncertain which track belongs to which target. The crossings themselves are called "odd" if the tracks cross straight through each other, forming an "X", or are called "even" if the tracks approach each other and then diverge. It was studied how often these different crossings occur due to objects separating in space. An analysis of the situation where an object splits into n objects led to the conclusion that all crossings were odd. If these n splits occur sequentially, however, even crossings were possible, but turned out to be extremely rare in a Monte Carlo simulation. Statistics about the odd crossings of this simulation were aggregated for their frequency, crossing angle, and crossing time. In addition, it was examined how well targets could be tracked through an individual crossing. An algorithm was devised to track targets through crossings using only data from Range Time plots, i.e. data about the targets" ranges over time. The performance of this algorithm was tested with a large set of Monte Carlo simulations. Another, smaller set, of Monte Carlo simulations were generated, and those for which this algorithm could not give an answer with certainty were re-analyzed by a human in a series of blinded tests, using data from a Range Doppler plot, i.e. data about the targets" range and radial velocity over time. It was determined that the performance of both tests increased as the targets" relative radial velocities and track times increased.-3-Statement of Authorship During her summer internship at MIT Lincoln Laboratory, Kathleen developed a test for evenness and oddness of Range Time track crossings for point scatterer targets, and evaluated its performance as a function of track crossing angle and length of track time. For this project, Kathleen extended the test to include dumbbell-shaped targets and evaluated its performance as a function of track crossing angle, length of track time, rate of tumble, and direction of radar line of sight. Matthew adapted a Doppler imaging algorithm written by Fannie Rogal, an MIT Lincoln Laboratory employee, during his summer internship at MIT Lincoln Laboratory. Matthew modified the code to test the minimum range separation required to discriminate two targets traveling at the same radial velocity, as a function of both targets' rates of spin, rates and angles of precession, target lengths, and radar line of sight. For this project, the code was modified to accept predetermined ballistic scenarios that led to Range Time track crossings. The script created time lapsed Range Doppler plots of the targets which were visually discriminated by a human. Alexander analyzed track crossing situations for a variety of crossing statistics. He algebraically derived crossing times for both the starburst and periodically separating ...