New Open Source Physics collection resources
http://www.compadre.org/OSP/
The latest material additions to the Open Source Physics.en-USCopyright 2014, ComPADRE.orgosp@compadre.orgosp@compadre.orgSun, 26 Oct 2014 11:24:27 ESThttp://blogs.law.harvard.edu/tech/rsshttp://www.compadre.org/portal/services/images/LogoSmallOSP.gifOpen Source Physics
http://www.compadre.org/OSP/
12535Gas-Liquid Coexistence by Gibbs Ensemble Model
http://www.compadre.org/OSP/items/detail.cfm?ID=13352
The Gas-Liquid Coexistence by Gibbs Ensemble Model illustrates the method introduced by Panagiotopoulos to simulate gas-liquid equilibrium. It combines NVT, NPT and ?VT Monte Carlo techniques in a single simulation using two boxes at given initial densities and no explicit interface, and setting the required temperature. When equilibrium is attained one of the boxes contains the gas, the other contains the liquid so that the chemical potentials and pressures turn equal in both boxes. In the so-called Gibbs Ensemble method there is no need to specify chemical potentials and pressures in advance, they are just natural sub-products of the simulations. The method is applied to the gas-liquid diagram of the Lennard-Jones system paving the way to the study of more complex systems. The number of molecules, initial densities and required temperature can be changed to probe the whole diagram. 3D animations of molecular moves are included. Some technical aspects concerned with finite size effects and the limitation of the method near the critical point are pointed out.
The Gas-Liquid Coexistence by Gibbs Ensemble Model was developed using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the jar file will run the program if Java is installed. You can modify this simulation if you have EJS installed by right-clicking within the map and selecting "Open Ejs Model" from the pop-up menu item.Thermo & Stat Mech/Phase Transitionshttp://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=13352Sun, 26 Oct 2014 11:24:27 ESThttp://www.compadre.org/OSP/items/detail.cfm?ID=13352Data Fitting JS Model
http://www.compadre.org/OSP/items/detail.cfm?ID=13350
The Data Fitting JS Model uses a least square fitting algorithm to fit a polynomial curve to a data set. Users can add points by clicking within the plotting panel. This model is designed to show how to use the numeric JavaScript library that is distributed with EjsS.
The Data Fitting JS Model was developed using the Easy Java/JavaScript Simulations (EjsS) version 5. Although EjsS is a Java program, it can create stand alone JavaScript programs that run in almost any PC or tablet.Mathematical Tools/Linear Algebra and Tensorshttp://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=13350Tue, 21 Oct 2014 15:59:03 ESThttp://www.compadre.org/OSP/items/detail.cfm?ID=13350Physlet Two-Dimensional Kinematics Illustrations Package
http://www.compadre.org/OSP/items/detail.cfm?ID=13348
The Physlet Two-Dimensional Kinematics Illustrations Package contains JavaScript adaptations of Physlet Illustrations from Physlet Physics Chapter 3. Students need to interact with the Physlet, but the answers to the kinematics questions posed in the Illustration are given or are easily determined from interacting with it. Some Illustrations provide examples of physics applications while others are designed to introduce a particular kinematics concept. Typical uses of Illustrations would include reading assignments prior to class and classroom demonstrations.
The Physlet Two-Dimensional Kinematics Illustrations Package was developed using the Easy Java/JavaScript Simulations (EjsS) version 5. Although EjsS is a Java program, it can create stand alone JavaScript programs that run in almost any PC or tablet.Classical Mechanics/Motion in Two Dimensionshttp://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=13348Wed, 08 Oct 2014 20:40:40 ESThttp://www.compadre.org/OSP/items/detail.cfm?ID=13348DNA Restriction Mapping Model
http://www.compadre.org/OSP/items/detail.cfm?ID=13347
The DNA Restriction Mapping Model simulates the cutting of a DNA molecule at each occurrence of the sequence GTGCAC or GTTAAC, turning the DNA strand into several smaller strands. These fragments can then be pieced together to create a map of the original DNA molecule, a process that is called Restriction Mapping. This model takes a set of DNA fragment lengths as input and returns all possible combinations that could produce the original DNA strand. To visualize the DNA molecule, the simulation draws a reconstruction using a different color to mark each fragment. It is possible for this reconstruction to have several solutions, or to have no solution at all.
The DNA Restriction Mapping Model is distributed as a ready-to-run (compiled) Java archive. Double clicking the jar file will run the program if Java is installed. You can modify this simulation if you have EJS installed by right-clicking within the map and selecting "Open Ejs Model" from the pop-up menu item.Modern Physics/Biophysicshttp://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=13347Wed, 08 Oct 2014 18:04:10 ESThttp://www.compadre.org/OSP/items/detail.cfm?ID=13347Synkope amusement park ride
http://www.compadre.org/OSP/items/detail.cfm?ID=13346
This EjsS Javascript 3D model simulates a ride in a Synkope attraction, located at Terra Mitica, Benidorm, Spain. People seat on the base cylinder, which is then balanced (pretty high!) while it rotates around its axis. The ride accelerates for some seconds, then stays at maximum balance, and finally slows down until stopping. Click on the "Throw objects" button to simulate the fall of objects released (or lost) from riders. This helps you figure out a reasonable safety perimeter.Classical Mechanics/Rotational Dynamicshttp://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=13346Wed, 01 Oct 2014 20:06:45 ESThttp://www.compadre.org/OSP/items/detail.cfm?ID=13346Molecular Dynamics, Metropolis Monte Carlo and Creutz's Demon Model
http://www.compadre.org/OSP/items/detail.cfm?ID=13344
The Molecular Dynamics, Metropolis Monte Carlo and Creutz's Demon Model compares canonical molecular dynamics and Monte Carlo versus microcanonical Creutz's demon simulations. The molecules interact in 3D through Lennard-Jones's potential and a wide range of densities, temperatures and energies can be simulated. The Monte Carlo computations sample the configuration and velocity spaces similarly to molecular dynamics. Thermodynamic properties, radial, speed and demon distribution functions are displayed allowing to assess the consistency between the ensembles and methods implemented. .
The Molecular Dynamics, Metropolis Monte Carlo and Creutz's Demon Model was developed using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the jar file will run the program if Java is installed. You can modify this simulation if you have EJS installed by right-clicking within the map and selecting "Open Ejs Model" from the pop-up menu item.Thermo & Stat Mech/Generalhttp://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=13344Tue, 16 Sep 2014 13:23:30 ESThttp://www.compadre.org/OSP/items/detail.cfm?ID=13344Hanoi Towers Puzzle Model
http://www.compadre.org/OSP/items/detail.cfm?ID=13343
The Hanoi Towers Puzzle Model shows a stack of different sized disks on the left most of three posts. The objective is to move the stack of disks from the left post to the right post while only moving one disk at a time and never placing larger disks on top of smaller disks. The puzzle is easily solved with stacks of one or two disks, but the complexity quickly grows as the number of disks increases. For example, three disks can be solved with seven moves, but seven disks require 127 moves. The user may manually solve the Hanoi Towers problem using the arrow buttons at the bottom of the display, but the main feature of the model is the recursive algorithm used to solve the puzzle algorithmically.
The Hanoi Towers Model was developed using the Easy Java JavaScript Simulation (EjsS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the jar file will run the program if Java is installed. You can modify this simulation if you have EJS installed by right-clicking within the map and selecting "Open Ejs Model" from the pop-up menu item.General Physics/Computational Physicshttp://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=13343Mon, 15 Sep 2014 16:55:17 ESThttp://www.compadre.org/OSP/items/detail.cfm?ID=13343Bell Gedanken Experiment Model
http://www.compadre.org/OSP/items/detail.cfm?ID=13341
The Bell Gedanken Experiment Model implements a simple 3D representation of Bell’s adaptation of the Einstein-Podolsky-Rosen apparatus. A central source prepares a singlet state for two Spin 1/2 particles with a specified z-component. Each arm of the apparatus has Stern-Gerlach detectors that can be rotated about the y axis. The simulation plots the data in a Up Up ?? pair number vs angle difference representation and compares the classical prediction to the quantum mechanical prediction for the expected value of pairs.
The Bell Gedanken Experiment Model was developed using version 5 of the Easy Java/JavaScript Simulations (EjsS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the jar file will run the program if Java is installed. You can modify this simulation if you have EjsS installed by right-clicking within the map and selecting "Open Ejs Model" from the pop-up menu item.
Quantum Physics/Entanglement and Quantum Informationhttp://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=13341Wed, 03 Sep 2014 18:11:13 ESThttp://www.compadre.org/OSP/items/detail.cfm?ID=13341Chaos and Instability in Integration Algorithms Model
http://www.compadre.org/OSP/items/detail.cfm?ID=13340
The Chaos and Instability in Integration Algorithms Model uses the the nonlinear and non-autonomous differential equation dx/dt = t - x^2 to show how careful one must be when choosing a differential equation solver, even for an apparently simple problem. The chaotic behaviors here detected do not seem an intrinsic property of the differential equation, though the patterns are startling similar to the May-Feigenbaum's standard map. Indeed they disappear with more robust integration algorithms. The chaos here invoked only means that for some algorithms and integration times the trajectories are not random, but are unpredictable. Apparently, in such cases, there is also no dependence on initial conditions, a typical characteristic of intrinsic chaotic systems. This application illustrates that using an adaptive algorithm is not only a question of speed and CPU use, but also of precision and stability and the care that must be taken to avoid wrong conclusions, especially when using computer packages as "black-boxes."
The Chaos and Instability in Integration Algorithms Model was developed using version 5 of the Easy Java/JavaScript Simulations (EjsS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the jar file will run the program if Java is installed. You can modify this simulation if you have EjsS installed by right-clicking within the map and selecting "Open Ejs Model" from the pop-up menu item.Mathematical Tools/Numerical Analysishttp://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=13340Mon, 01 Sep 2014 17:41:59 ESThttp://www.compadre.org/OSP/items/detail.cfm?ID=13340Grid Chemical Kinetics Monte Carlo Model
http://www.compadre.org/OSP/items/detail.cfm?ID=13339
The Grid Chemical Kinetics Monte Carlo Model simulates three simple reactions (with closed-form analytic solutions) to illustrate how the Monte Carlo method can be used to compute a reaction's time evolution time and to show that fluctuations (ever present in the real world) occur naturally in the reaction. The number of reacting molecules and rate constants can be changed in order to assess and visualize different reaction scenarios.
The Grid Chemical Kinetics Monte Carlo Model was developed using version 5 of the Easy Java/JavaScript Simulations (EjsS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the jar file will run the program if Java is installed. You can modify this simulation if you have EjsS installed by right-clicking within the map and selecting "Open Ejs Model" from the pop-up menu item.Thermo & Stat Mech/Kinetics and Dynamics/Approach to Equilibriumhttp://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=13339Mon, 01 Sep 2014 17:20:22 ESThttp://www.compadre.org/OSP/items/detail.cfm?ID=13339Asset Exchange Model Package
http://www.compadre.org/OSP/items/detail.cfm?ID=13337
The EjsS Asset Exchange Model Package contains JavaScript models to investigate the the transfer of wealth in a simple economic model consisting of N buyers and sellers, known as agents, who spend their time buying and selling goods at a yard sale. In this economic model, two agents A and B are chosen at random and goods are exchanged. If the price of the item is correct, neither agent gains or looses wealth but this is uninteresting and unrealistic. In a realistic transaction an agent can either pay too much or get a bargain so that one agent becomes slightly richer while the other agent becomes poorer. What happens to the wealth of agent wA if this process is repeated many times and if we assume that the agent receiving the bargain is chosen at random so that sometimes agent A gains and sometimes agent A looses in the transaction. In other words, neither agent is always shrewd or always gullible so that all agents have an equal chance of getting rich. Does this model produce an equitable distribution of wealth?
The EjsS Asset Exchange Model Package was developed using the Easy Java/JavaScript Simulations (EjsS) version 5 authoring tool. Although EjsS is a Java program, it can create stand alone JavaScript programs that run in almost any PC or tablet.Thermo & Stat Mech/Probability/Random Walkshttp://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=13337Thu, 28 Aug 2014 17:42:59 ESThttp://www.compadre.org/OSP/items/detail.cfm?ID=13337Simple Foucault Precession Package
http://www.compadre.org/OSP/items/detail.cfm?ID=13335
The Simple Foucault Precession Launcher package shows seven examples of a particle moving on a plane that is inclined at a fixed angle with respect to the xy plane and rotating at a constant angle with respect to the z axis. This simple system is used to model the rate of Foucault precession.
The materials in this resource are described in an article titled "Foucault precession manifested in a simple system."Classical Mechanics/Relative Motion/Rotating Reference Frameshttp://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=13335Wed, 20 Aug 2014 18:50:12 ESThttp://www.compadre.org/OSP/items/detail.cfm?ID=13335Vector Components Tutorial Models
http://www.compadre.org/OSP/items/detail.cfm?ID=13334
The Vector Components Tutorial Models demonstrate how to compute and use a Cartesian grid to perform vector arithmetic. The two models cataloged in this item demonstrate:
<ul>
<li>vector components, and</li>
<li>vector addition.</li>
</ul>
You can modify these simulations if you have Ejs installed by right-clicking within the plot and selecting “Open Ejs Model” from the pop-up menu item.Mathematical Tools/Vector Algebra/Vector Additionhttp://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=13334Sat, 16 Aug 2014 16:00:27 ESThttp://www.compadre.org/OSP/items/detail.cfm?ID=13334Vibrations and Wave Tutorial Models
http://www.compadre.org/OSP/items/detail.cfm?ID=13332
The Vibrations and Wave Tutorial Models demonstrate how the superposition principle gives rise to wave phenomena, such as standing waves and beats. The five models cataloged in this item demonstrate:
<ul>
<li>simple harmonic motion,</li>
<li>history graphs,</li>
<li>standing waves,</li>
<li>standing waves on an infinite string, and</li>
<li>beats.</li>
</ul>
You can modify these simulations if you have Ejs installed by right-clicking within the plot and selecting “Open Ejs Model” from the pop-up menu item.Oscillations & Waves/Wave Motionhttp://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=13332Mon, 11 Aug 2014 08:16:27 ESThttp://www.compadre.org/OSP/items/detail.cfm?ID=13332Parallel Two-Dimensional Time-Dependent Schrödinger Equation Model
http://www.compadre.org/OSP/items/detail.cfm?ID=13331
The Parallel Two-Dimensional Time-Dependent Schrödinger Equation Model implements a staggered-time algorithm in which the real and imaginary parts of the wave function on a 2D grid are defined at alternate times as described by Visscher. Because the each part of the wave fucntion (real or imaginary) depends on the other part, the update loop can be parallelized. The algorithm is well suited for pedagogic applications because it is second-order accurate in time and has the speed and simplicity of explicit methods and the accuracy and stability of second-order implicit methods, such as Crank-Nicholson.
The Parallel Two-Dimensional Ising Model was developed by Wolfgang Christian using the Easy Java/JavaScript Simulations (EjsS) version 5 modeling tool. It is based on a Java program from An Introduction to Computer Simulation Methods and is distributed as a ready-to-run Java program (jar file) and as EjsS source code (xml file).Quantum Physics/Foundations and Measurements/Time Dependencehttp://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=13331Fri, 08 Aug 2014 19:43:56 ESThttp://www.compadre.org/OSP/items/detail.cfm?ID=13331Boltzmann Machine Model
http://www.compadre.org/OSP/items/detail.cfm?ID=13330
The Boltzmann Machine Model simulates a ping-pong ball moving around on two flat surfaces that are connected by a ramp. This ball is given occasional random "kicks" which cause the ball to move unpredictably. Remarkably, this simple system is a macroscopic example of a two-level system* that obeys the Boltzmann distribution function. The Boltzmann distribution is typically associated with a <i>microscopic</i> system in contact with a heat bath; but in this case, the system is <i>macroscopic</i> and easy to visualize, and the random kicks serve the role of the heat bath. In Ref. 1, "Squiggle Balls" were used to produce the kicks for the Boltzmann Machine experiment, whereas in this simulation we use randomly generated velocities to produce the kicks. The advantage to using this simulation (as opposed to the experiment) is that parameters can be manipulated, and results can be obtained, much more quickly and easily.
The Boltzmann Machine Model was developed using the Easy Java/JavaScript Simulations (EjsS) modeling tool version 5. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_fmu_BoltzmannMachine.jar file will run the program if Java is installed. You can modify this simulation if you have EJS installed by right-clicking within the map and selecting "Open Ejs Model" from the pop-up menu item.
*This is a “two-level” system in the sense that there are two different values of potential energy: the value on the top surface and the value on the bottom surface.
1. J. J. Prentis, American Journal of Physics 68, 1073 (2000).
This work was supported in part by NSF-TUES grant DUE-1140034.
Thermo & Stat Mech/Ensembles/Boltzmann Distributionhttp://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=13330Fri, 01 Aug 2014 20:56:23 ESThttp://www.compadre.org/OSP/items/detail.cfm?ID=13330Lennard-Jones 2D Demon Model
http://www.compadre.org/OSP/items/detail.cfm?ID=13329
The Lennard-Jones 2D Demon Model is a Monte Carlo simulation of Lennard-Jones particles in two dimensions interacting with a Monte Carlo demon. A Monte Carlo demon is an extra degree of freedom that is allowed to transfer energy as it attempts to change the state of the system. The demon keeps track of its own energy and can take or give energy to a particle as it interacts with a randomly chosen particle. Because the demon cannot have negative energy, the total energy of the system remains constant -- as it should in the microcanonical ensemble. The demon is, in effect, a thermometer. Its extra degree of freedom perturbs the system very little and the average demon energy is proportional to the temperature of the system. (See Statistical and Thermal Physics notes by H. Gould and J. Tobochnik.)
The Lennard-Jones 2D Demon Model was developed using the Easy Java/JavaScript Simulations (EjsS) version 5 modeling tool. It is distributed as a ready-to-run (compiled) Java archive.Thermo & Stat Mech/Thermal Properties of Matter/Temperaturehttp://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=13329Fri, 01 Aug 2014 19:36:18 ESThttp://www.compadre.org/OSP/items/detail.cfm?ID=13329Lennard-Jones 2D Metropolis Model
http://www.compadre.org/OSP/items/detail.cfm?ID=13325
The Lennard-Jones 2D Metropolis Model is a Monte Carlo simulation of Lennard-Jones particles in two dimensions in contact with a heat bath. The default initial condition is a rectangular configuration of N=64 particles in a box of length L = 18 and a temperature T= 1.
The Lennard-Jones 2D Metropolis Model was developed using the Easy Java/JavaScript Simulations (EjsS) version 5 modeling tool. It is distributed as a ready-to-run (compiled) Java archive.Thermo & Stat Mech/Models/Lennard-Jones Potentialhttp://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=13325Sun, 27 Jul 2014 19:13:17 ESThttp://www.compadre.org/OSP/items/detail.cfm?ID=13325Saving and Sharing Tracker Experiments Tutorial
http://www.compadre.org/OSP/items/detail.cfm?ID=13321
The Saving and Sharing Tracker Experiments Tutorial was recorded by Doug Brown, the creator Tracker, to lead users through the process of exporting a Tracker zip file (TRZ) and building a Tracker Digital Library. The tutorial first shows how to use Tracker's video export options and how to include supplemental documents, such as a lab report, in the TRZ package. The tutorial then shows how to organize multiple Tracker experiments using Tracker's Digital Library Browser.
Additional Tracker resources including Tracker help and sample videos are available from the the <a href="https://www.cabrillo.edu/~dbrown/tracker/">Tracker home page at Cabrillo College."</a> and from the Open Source Physics Collection.Education Practices/Curriculum Development/Laboratoryhttp://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=13321Sun, 20 Jul 2014 20:56:26 ESThttp://www.compadre.org/OSP/items/detail.cfm?ID=13321Tea Cups Ride JS Model
http://www.compadre.org/OSP/items/detail.cfm?ID=13319
The Tea Cups Ride JS Model shows the motion on an amusement park ride. The 200 kg cups and the 80 kg riders are free to rotate around their center of the cup. The ride platform and cup platform are driven by motors (shown in green) but the motion of the riders about the cup center is not driven. Click on a cup to seat a person there before clicking Play/Pause to run the ride. The ride accelerates for some seconds, then stays at maximum angular speed (of the attraction and the platforms) and then slows down until stopping.
This simulation is based on an original idea by Virgina Abellán, Roberto Pérez, and José David Rodríguez. Students of "Modelling Laboratory", 3rd year of the Math Degree at the University of Murcia, Spain. Academic year 2013-2014. The model was developed using the Easy Java Simulations (EjsS) version 5. It is distributed as a ready-to-run html page and requires only a browser with JavaScript support.This model simulates a ride in a Tea Cups attraction (as seen from above).Classical Mechanics/Rotational Dynamicshttp://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=13319Mon, 07 Jul 2014 12:04:11 ESThttp://www.compadre.org/OSP/items/detail.cfm?ID=13319