http://www.compadre.org/STP/ The latest material additions to the Statistical and Thermal Physics. en-US Copyright 2010, ComPADRE.org stp@compadre.org stp@compadre.org Thu, 11 Feb 2010 18:43:18 EST http://blogs.law.harvard.edu/tech/rss http://www.compadre.org/portal/services/images/LogoSmallSTP.gif http://www.compadre.org/STP/ 125 35 http://www.compadre.org/STP/items/detail.cfm?ID=4440 This presentation from the 2006 PTEC Conference presents education research on topics in thermodynamics. Student responses to conceptual thermodynamics questions, and the conceptions they reveal, are presented. Tutorial materials developed to help students gain a better understanding of the topic are also presented. Thermodynamics & Statistical Mechanics/First Law http://www.compadre.org/STP/bulletinboard/Thread.cfm?ID=4440 Thu, 11 Feb 2010 18:43:18 EST http://www.compadre.org/STP/items/detail.cfm?ID=4440 http://www.compadre.org/STP/items/detail.cfm?ID=8925 We are engaged in a research project to study teaching and learning in upper-level thermal physics courses. We have begun to explore student functional understanding of mathematical concepts when applied in thermal physics contexts. We report here preliminary findings associated with partial differentiation and the Maxwell relations, which equate mixed second partial derivatives of various state functions. Our results suggest that students are often unable to apply the appropriate mathematical concepts and operations to the physical situations encountered in the course, despite having taken the prerequisite mathematics courses. General Physics/Physics Education Research http://www.compadre.org/STP/bulletinboard/Thread.cfm?ID=8925 Thu, 11 Feb 2010 18:40:18 EST http://www.compadre.org/STP/items/detail.cfm?ID=8925 http://www.compadre.org/STP/items/detail.cfm?ID=8926 We report data on upper-level student understanding of entropy and the Second Law of Thermodynamics when comparing the isothermal and free expansions of an ideal gas. Data from pre- and post-instruction written questions are presented, and several noteworthy features of student performance are identified and discussed. These features include ways students think about these topics prior to instruction as well as specific difficulties and other interesting aspects of student thought that persist after instruction. Implications for future research are also addressed. Thermodynamics & Statistical Mechanics/Second and Third Law/Entropy http://www.compadre.org/STP/bulletinboard/Thread.cfm?ID=8926 Thu, 11 Feb 2010 18:36:49 EST http://www.compadre.org/STP/items/detail.cfm?ID=8926 http://www.compadre.org/STP/items/detail.cfm?ID=2669 Many studies have shown that pre-university students have substantial learning difficulties related to heat, temperature, and related concepts. However, very few investigations have been reported that focus on student learning of thermal physics concepts at the university level. Here we report on an investigation of reasoning regarding heat, work, and the first law of thermodynamics among students in an introductory calculus-based general physics course. Responses to written questions by 653 students in three separate courses were very consistent with results of detailed individual interviews carried out with 32 students in a fourth course. Although most students seemed to acquire a reasonable grasp of the state function concept, it was found that there was a widespread and persistent tendency to improperly over-generalize this concept to apply to both work and heat. A large majority thought that net work done and/or net heat absorbed by a system during a cyclic process must be zero, while only 20% or fewer were able to make effective use of the first law of thermodynamics even after instruction was completed. Students' difficulties seemed to stem in part from the fact that heat, work, and internal energy all share the same units. Results were consistent with those of previously published studies of students in U.S. and European universities, but portray a pervasiveness of confusion regarding process-dependent quantities that was previously unreported. The implication is that significant enhancements of current standard instruction may be required for students to master basic thermodynamic concepts. Thermodynamics & Statistical Mechanics/First Law http://www.compadre.org/STP/bulletinboard/Thread.cfm?ID=2669 Mon, 22 Jun 2009 16:32:03 EST http://www.compadre.org/STP/items/detail.cfm?ID=2669 http://www.compadre.org/STP/items/detail.cfm?ID=2745 We report on an investigation of student understanding of the first law of thermodynamics. The students involved were drawn from first-year university physics courses and a second-year thermal physics course. The emphasis was on the ability of the students to relate the first law to the adiabatic compression of an ideal gas. Although they had studied the first law, few students recognized its relevance. Fewer still were able to apply the concept of work to account for a change in temperature in an adiabatic process. Instead most of the students based their predictions and explanations on a misinterpretation of the ideal gas law. Even when ideas of energy and work were suggested, many students were unable to give a correct analysis. They frequently failed to differentiate the concepts of heat, temperature, work, and internal energy. Some of the difficulties that students had in applying the concept of work in a thermal process seemed to be related to difficulties with mechanics. Our findings also suggest that a misinterpretation of simple microscopic models may interfere with student ability to understand macroscopic phenomena. Implications for instruction in thermal physics and in mechanics are discussed. Thermodynamics & Statistical Mechanics/First Law/Adiabatic Processes http://www.compadre.org/STP/bulletinboard/Thread.cfm?ID=2745 Mon, 22 Jun 2009 16:27:41 EST http://www.compadre.org/STP/items/detail.cfm?ID=2745 http://www.compadre.org/STP/items/detail.cfm?ID=9170 A new statement of the second law of thermodynamics is given. The law leads almost effortlessly, for very general closed systems, to a definition of absolute entropy S, a demonstration that ΔS>0 in adiabatic processes, a definition of temperature, and a demonstration that dS>δQ/T in quasistatic processes. Entropy is given a clear physical meaning. Thermodynamics & Statistical Mechanics/Second and Third Law/Entropy http://www.compadre.org/STP/bulletinboard/Thread.cfm?ID=9170 Mon, 22 Jun 2009 16:15:35 EST http://www.compadre.org/STP/items/detail.cfm?ID=9170 http://www.compadre.org/STP/items/detail.cfm?ID=9168 All too often, courses in thermodynamics and statistical mechanics barrage their students with numerous equations that are left unexamined and uninvestigated. This note explains how to pause, examine a thermodynamic equation, and render it more meaningful. Three techniques are discussed: (1) design two experiments that would measure the quantities on either side of the equality; (2) examine special cases; (3) consider the consequences if the equality failed to hold. Thermodynamics & Statistical Mechanics/General http://www.compadre.org/STP/bulletinboard/Thread.cfm?ID=9168 Mon, 22 Jun 2009 16:00:25 EST http://www.compadre.org/STP/items/detail.cfm?ID=9168 http://www.compadre.org/STP/items/detail.cfm?ID=2823 Heat and thermodynamics are traditionally taught in the introductory physics course from a predominantly macroscopic point of view. However, it is advantageous to adopt a more modern approach that systematically builds on students' knowledge of the atomic structure of matter and of elementary mechanics. By focusing on the essential physics without requiring more than elementary classical mechanics, this approach can be made sufficiently simple to be readily teachable during five or six weeks of an ordinary calculus-based introductory physics course. This approach can be highly unified, using atomic considerations to infer the properties of macroscopic systems while also enabling thermodynamic analyses independent of specific atomic models. Furthermore, this integrated point of view provides a deeper physical understanding of basic concepts (such as internal energy, heat, entropy, and absolute temperature) and of important phenomena (such as equilibrium, fluctuations, and irreversibility). Thermodynamics & Statistical Mechanics/General http://www.compadre.org/STP/bulletinboard/Thread.cfm?ID=2823 Mon, 22 Jun 2009 15:22:47 EST http://www.compadre.org/STP/items/detail.cfm?ID=2823 http://www.compadre.org/STP/items/detail.cfm?ID=8846 The EJS Uniform Spherical Distribution Model shows how to pick a random point on the surface of a sphere. It shows a distribution generated by (incorrectly) picking points using a uniform random distribution as well as the correct weighted distribution. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting “Open Ejs Model” from the pop-up menu item. The Uniform Spherical Distribution Model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_stp_UniformSphericalDistribution.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs. Thermodynamics & Statistical Mechanics/Probability/Probability Density http://www.compadre.org/STP/bulletinboard/Thread.cfm?ID=8846 Mon, 27 Apr 2009 10:04:45 EST http://www.compadre.org/STP/items/detail.cfm?ID=8846 http://www.compadre.org/STP/items/detail.cfm?ID=8845 The EJS Random Walk 2D Model simulates a 2-D random walk. You can change the number of walkers and probability of going a given direction. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting “Open Ejs Model” from the pop-up menu item. The Random Walk 2D Model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_stp_RandomWalk2D.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs. Thermodynamics & Statistical Mechanics/Probability/Random Walks http://www.compadre.org/STP/bulletinboard/Thread.cfm?ID=8845 Mon, 27 Apr 2009 09:29:25 EST http://www.compadre.org/STP/items/detail.cfm?ID=8845 http://www.compadre.org/STP/items/detail.cfm?ID=8844 The EJS Random Walk 1D Continuous Model simulates a 1-D random walk with a variable step size. You can change the number of walkers and probability of going right and left. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting “Open Ejs Model” from the pop-up menu item. The Random Walk 1D Continuous Model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_stp_RandomWalk1D.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs. Thermodynamics & Statistical Mechanics/Probability/Random Walks http://www.compadre.org/STP/bulletinboard/Thread.cfm?ID=8844 Mon, 27 Apr 2009 09:15:46 EST http://www.compadre.org/STP/items/detail.cfm?ID=8844 http://www.compadre.org/STP/items/detail.cfm?ID=8830 The EJS Binomial Distribution Model calculates the binomial distribution. You can change the number of trials and probability. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting “Open Ejs Model” from the pop-up menu item. The Binomial Distribution Model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_stp_BinomialDistribution.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs. Thermodynamics & Statistical Mechanics/Probability/Binomial Distribution http://www.compadre.org/STP/bulletinboard/Thread.cfm?ID=8830 Thu, 23 Apr 2009 16:52:55 EST http://www.compadre.org/STP/items/detail.cfm?ID=8830 http://www.compadre.org/STP/items/detail.cfm?ID=8005 This applet simulates the binomial distribution. The user can control the population proportion, the sample size and the number of samples. Once the samples are drawn, the number of successes are plotted. The user can choose to count the successes greater than a certain value. They are also able to view theoretical values. This is part of a larger collection of applets on statistics from the California Poly San Luis Obispo. Thermodynamics & Statistical Mechanics/Probability/Binomial Distribution http://www.compadre.org/STP/bulletinboard/Thread.cfm?ID=8005 Tue, 31 Mar 2009 16:11:23 EST http://www.compadre.org/STP/items/detail.cfm?ID=8005 http://www.compadre.org/STP/items/detail.cfm?ID=7970 This applet demonstrates a histogram. The user can edit the data or choose different data samples. The user is able to guess the mean/median, deviation, and IQR. It can then display the actual mean/median, deviation and IQR. This is part of a larger collection of applets on statistics from the California Poly San Luis Obispo. Thermodynamics & Statistical Mechanics/Probability http://www.compadre.org/STP/bulletinboard/Thread.cfm?ID=7970 Tue, 31 Mar 2009 16:10:52 EST http://www.compadre.org/STP/items/detail.cfm?ID=7970 http://www.compadre.org/STP/items/detail.cfm?ID=7975 This applet samples words. The user can control the sample size and the number of samples. It displays the number, the word, the number of letters, whether it is long and whether or not it is a noun. Then, each one is plotted. This is part of a larger collection of applets on statistics from the California Poly San Luis Obispo. Thermodynamics & Statistical Mechanics/Probability http://www.compadre.org/STP/bulletinboard/Thread.cfm?ID=7975 Tue, 31 Mar 2009 16:10:24 EST http://www.compadre.org/STP/items/detail.cfm?ID=7975 http://www.compadre.org/STP/items/detail.cfm?ID=7977 This applet draws a sample of senators (from Senators in 2005). The user can control the sample size and the number of samples. The applet displays the senator's name, number of years in the senate, their party and gender. Each set is then plotted. The mean and standard deviation is displayed. This is part of a larger collection of applets on statistics from the California Poly San Luis Obispo. Thermodynamics & Statistical Mechanics/Probability http://www.compadre.org/STP/bulletinboard/Thread.cfm?ID=7977 Tue, 31 Mar 2009 16:09:41 EST http://www.compadre.org/STP/items/detail.cfm?ID=7977 http://www.compadre.org/STP/items/detail.cfm?ID=8685 The STP Entropy Einstein Solid program calculates the entropy of two Einstein solids that can exchange energy. The purpose of this calculation is to illustrate that the entropy is a maximum at thermal equilibrium. The default system is two Einstein solids with 50 particles each and total energy E =200. STP EntropyEinsteinSolid is part of a suite of Open Source Physics programs that model aspects of Statistical and Thermal Physics (STP). The program is distributed as a ready-to-run (compiled) Java archive. Double clicking the stp_EntropyEinsteinSolid.jar file will run the program if Java is installed on your computer. Additional programs can be found by searching ComPADRE for Open Source Physics, STP, or Statistical and Thermal Physics. Thermodynamics & Statistical Mechanics/Second and Third Law/Entropy http://www.compadre.org/STP/bulletinboard/Thread.cfm?ID=8685 Fri, 13 Mar 2009 10:49:37 EST http://www.compadre.org/STP/items/detail.cfm?ID=8685 http://www.compadre.org/STP/items/detail.cfm?ID=8306 The EJS Lennard-Jones Potential model shows the dynamics of a particle of mass m within this potential. You can drag particle to change its position and you can drag the energy-line to change its total energy. The Lennard-Jones potential function is a reasonably accurate model of interactions between noble gas atoms. The binding energy epsilon is the depth of the potential well and minimum molecular separation are set equal to unity. This simulation uses uses a natural system of units the mass and the depth of the Lennard-Jones potential set equal to 1. For argon (for example), the unit of distance is 3.4 angstroms, the unit of mass is 40 atomic mass units, and the unit of energy is 0.01 electron-volts; the corresponding unit of time is then 2.2 picoseconds, the unit of velocity is 160 meters per second. The Lennard-Jones Potential model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_stp_md_LennardJones.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for classical mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs. Thermodynamics & Statistical Mechanics/Models/Lennard-Jones Potential http://www.compadre.org/STP/bulletinboard/Thread.cfm?ID=8306 Fri, 13 Mar 2009 10:48:55 EST http://www.compadre.org/STP/items/detail.cfm?ID=8306 http://www.compadre.org/STP/items/detail.cfm?ID=8684 The STP LJ Thermal Equilibrium program simulates the interaction between two systems of Lennard-Jones particles brought into thermal contact. The purpose of this simulation is to explore the nature of thermal equilibrium and the relation, if any, between the kinetic and potential energies of two systems in thermal contact. The two initially isolated systems have 81 (red) and 64(green) particles by default. STP LJThermalEquilibrium is part of a suite of Open Source Physics programs that model aspects of Statistical and Thermal Physics (STP). The program is distributed as a ready-to-run (compiled) Java archive. Double-clicking the stp_LJThermalEquilibrium.jar file will run the program if Java is installed on your computer. Additional programs can be found by searching ComPADRE for Open Source Physics, STP, or Statistical and Thermal Physics. Thermodynamics & Statistical Mechanics/First Law/Thermal Equilibrium http://www.compadre.org/STP/bulletinboard/Thread.cfm?ID=8684 Fri, 13 Mar 2009 10:47:45 EST http://www.compadre.org/STP/items/detail.cfm?ID=8684 http://www.compadre.org/STP/items/detail.cfm?ID=8303 The EJS Molecular Dynamics model is constructed using the Lennard-Jones potential truncated at a distance of 3 molecular diameters. The motion of the molecules is governed by Newton's laws, approximated using the Verlet algorithm with the indicated time step. For sufficiently small time steps dt, the system's total energy should be approximately conserved. The Molecular Dynamics model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_stp_md_MolecularDynamics.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for classical mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs. Thermodynamics & Statistical Mechanics/Models/Lennard-Jones Potential http://www.compadre.org/STP/bulletinboard/Thread.cfm?ID=8303 Fri, 13 Mar 2009 10:42:35 EST http://www.compadre.org/STP/items/detail.cfm?ID=8303