http://www.compadre.org/OSP/ The latest material additions to the Open Source Physics. en-US Copyright 2008, ComPADRE.org managingEditor@compadre.org osp@compadre.org Tue, 02 Dec 2008 05:50:55 EST http://blogs.law.harvard.edu/tech/rss http://www.compadre.org/portal/services/images/LogoSmallOSP.gif http://www.compadre.org/OSP/ 125 35 http://www.compadre.org/OSP/items/detail.cfm?ID=8373 The EJS Elastic Collision Model allows the user to simulate a two-dimensional elastic collision between hard disks. The user can modify the mass, position and velocity of each disk using the sliders. Both disks are draggable and the center of mass is shown a a cross in the simulation. The Elastic Collision 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_ntnu_mech_ElasticCollision.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 Open Source Physics programs for quantum mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or EJS. Classical Mechanics/Linear Momentum/Collisions in Two Dimensions http://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=8373 Tue, 02 Dec 2008 05:50:55 EST http://www.compadre.org/OSP/items/detail.cfm?ID=8373 http://www.compadre.org/OSP/items/detail.cfm?ID=8331 The EJS Multiple Slit Diffraction model allows the user to simulate Fraunhofer diffraction through single or multiple slits. The user can modify the number of slits, the slit width, the slit separation and the wavelength of the incident light. The scale of the diffraction pattern can also be changed and a plot of the light intensity can be toggled on and off with a checkbox. The Multiple Slit Diffraction 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_ntnu_optics_MultipleSlitDiffraction.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 Open Source Physics programs for quantum mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or EJS. Optics/Diffraction http://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=8331 Sat, 22 Nov 2008 18:09:44 EST http://www.compadre.org/OSP/items/detail.cfm?ID=8331 http://www.compadre.org/OSP/items/detail.cfm?ID=8327 The Circular Well Superposition simulation displays the time evolution of the position-space wave function in an infinite 2D circular well. The default configuration shows the first excited state with zero angular momentum. Additional eigenstates can be added using a button in the eigenstate coefficient table. Circular Well Superpostion 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_qm_Superposition2DCircularWell.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 Open Source Physics programs for quantum mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or EJS. Quantum Physics/Bound State Systems http://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=8327 Fri, 21 Nov 2008 16:56:39 EST http://www.compadre.org/OSP/items/detail.cfm?ID=8327 http://www.compadre.org/OSP/items/detail.cfm?ID=8311 The EJSMagnetic Field from Loops model computes the B-field created by an electric current through a straight wire, a closed loop, and a solenoid. Users can adjust the vertical position of the slice through the 3D field. The Magnetic Field from Loops 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_ntnu_MagneticFielfFromLoops.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. Electricity & Magnetism/Magnetic Fields and Forces/Fields and Currents http://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=8311 Mon, 17 Nov 2008 11:15:17 EST http://www.compadre.org/OSP/items/detail.cfm?ID=8311 http://www.compadre.org/OSP/items/detail.cfm?ID=8307 The Balls in a Box model shows a system of particles is very sensitive to its initial conditions. In general, an isolated system of many particles that is prepared in a nonrandom configuration will change in time so as to approach its most random configuration where it is in equilibrium. What happens if we choose the initial conditions in a very special way? The default initial condition corresponds to eight stationary particles perfectly aligned on the x-axis. Two particles approach from the left and the right. What happens when these particles collide with the eight stationary particles? The Ejs model solves Newton's second law of motion numerically but pauses when a collision is detected. This is called an Ejs event. Conservation of energy and momentum are applied at the event and the simulation is resumed. The Balls in a Box 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_sto_BallsInBox.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. Classical Mechanics/Linear Momentum/Conservation of Linear Momentum http://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=8307 Sun, 16 Nov 2008 09:30:02 EST http://www.compadre.org/OSP/items/detail.cfm?ID=8307 http://www.compadre.org/OSP/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_LennardJonesPotential.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/OSP/bulletinboard/Thread.cfm?ID=8306 Sun, 16 Nov 2008 09:16:45 EST http://www.compadre.org/OSP/items/detail.cfm?ID=8306 http://www.compadre.org/OSP/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_MultipleCoinToss.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/OSP/bulletinboard/Thread.cfm?ID=8303 Sat, 15 Nov 2008 23:23:47 EST http://www.compadre.org/OSP/items/detail.cfm?ID=8303 http://www.compadre.org/OSP/items/detail.cfm?ID=8302 The Ejs Multiple Coin Toss model displays the result of the flipping of N coins. The result of each set of coin flips is shown by the image of the pennies on the screen and the complete results of the tossing experiment is shown on a graph of the cumulative probability of heads. The number of coins flipped, N, and change the "fairness" of the coin by setting the probability of a "heads" result, p, can be set via text boxes. 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. Ejs Multiple Coin Toss 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_MultipleCoinToss.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. Other Sciences/Mathematics http://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=8302 Sat, 15 Nov 2008 17:38:36 EST http://www.compadre.org/OSP/items/detail.cfm?ID=8302 http://www.compadre.org/OSP/items/detail.cfm?ID=8301 The EJS Molecular Dynamics Demonstration 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. Users can select various initial configurations using the drop down menu. 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_MultipleCoinToss.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/OSP/bulletinboard/Thread.cfm?ID=8301 Sat, 15 Nov 2008 14:39:32 EST http://www.compadre.org/OSP/items/detail.cfm?ID=8301 http://www.compadre.org/OSP/items/detail.cfm?ID=8287 A description of how to build Java Web Start applications using the OSP library. Integrates the OpenSourcePhysics .jar library files and the Python classes generated by Jython during compiling time with jythonc. General Physics/Computational Physics http://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=8287 Thu, 13 Nov 2008 12:13:22 EST http://www.compadre.org/OSP/items/detail.cfm?ID=8287 http://www.compadre.org/OSP/items/detail.cfm?ID=8292 The Ejs Strange Harmonic Oscillator model displays the motion of two masses connected by a massless rigid rod and the masses may move without friction along two perpendicular rails in a horizontal table. The energy of the oscillator system can be changed via a slider. 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. Ejs Strange Harmonic Oscillator 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_ehu_oscillations_strange.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. Oscillations & Waves/Oscillations/Simple Harmonic Motion http://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=8292 Tue, 11 Nov 2008 00:32:09 EST http://www.compadre.org/OSP/items/detail.cfm?ID=8292 http://www.compadre.org/OSP/items/detail.cfm?ID=8291 The Ejs Quartic Oscillator model displays the motion of a bead moving without friction along a horizontal rod, while tied to two symmetric springs. Both the motion of the masses and the phase space plot are shown in the simulation. The natural length of the springs can be changed via textboxes. 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. Ejs Quartic Oscillator Phasor 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_ehu_oscillations_quartic.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. Oscillations & Waves/Oscillations/Non-Linear Systems http://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=8291 Tue, 11 Nov 2008 00:24:22 EST http://www.compadre.org/OSP/items/detail.cfm?ID=8291 http://www.compadre.org/OSP/items/detail.cfm?ID=8290 The Ejs Damped Driven Harmonic Oscillator Phasor model displays the motion of damped driven harmonic oscillator. The resulting differential equation can be extended into the complex plane, and the resulting complex solution is displayed with the real part of this solution being the position of the oscillator. The natural frequency of the oscillator, the damping coefficient, and the driving force and driving frequency can be changed via textboxes. 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. Ejs Damped Driven Harmonic Oscillator Phasor 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_ehu_oscillations_phasors.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. Oscillations & Waves/Oscillations/Damped Oscillators http://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=8290 Tue, 11 Nov 2008 00:16:20 EST http://www.compadre.org/OSP/items/detail.cfm?ID=8290 http://www.compadre.org/OSP/items/detail.cfm?ID=8289 The Ejs Harmonics and Fourier Series model displays the sum of harmonics via a Fourier series to yield a new wave. The amplitude of each harmonic as well as the phase of that harmonic can be changed via sliders. In addition, several pre-set functions can be chosen to display. 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. Ejs Harmonics and Fourier Series 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_ehu_oscillations_harmonics.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. Oscillations & Waves/Wave Motion/Transverse Pulses and Waves http://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=8289 Tue, 11 Nov 2008 00:03:07 EST http://www.compadre.org/OSP/items/detail.cfm?ID=8289 http://www.compadre.org/OSP/items/detail.cfm?ID=8288 The Ejs Spring Pendulum model displays the model of a hollow mass that moves along a rigid rod that is also connected to a spring. The mass, therefore, undergoes a combination of spring and pendulum oscillations. The initial position and velocities, as well as the spring constant can be changed via textboxes. 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. Ejs Spring Pendulum 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_ehu_oscillations_elastic.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. Oscillations & Waves/Oscillations/Springs and Oscillators http://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=8288 Mon, 10 Nov 2008 23:50:49 EST http://www.compadre.org/OSP/items/detail.cfm?ID=8288 http://www.compadre.org/OSP/items/detail.cfm?ID=8263 The EJS Oscillator Chain model shows a one-dimensional linear array of coupled harmonic oscillators with fixed ends. This model can be used to study the propagation of waves in a continuous medium and the vibrational modes of a crystalline lattice. The Ejs model shown here contains 31 coupled oscillators equally spaced within the interval [0, 2 pi] with fixed ends. Ejs Oscillator Chain 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_mech_osc_OscillatorChain.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. Oscillations & Waves/Oscillations/Coupled Oscillations http://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=8263 Wed, 05 Nov 2008 22:19:49 EST http://www.compadre.org/OSP/items/detail.cfm?ID=8263 http://www.compadre.org/OSP/items/detail.cfm?ID=8257 The EJS Thick Lens model allows the user to simulate a lens (mirror) by adjusting the physical properties of a transparent (reflecting) object and observing the object's effect on a beam of light.  The user can adjust the concavity of the sides, the index of refraction and its environment, and the height and width of the object as well as the size of the incident light and the horizontal position of the transparent object.  Spherical aberration can be observed at large angles. You can examine and 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. Ejs Thick Lens 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_ntnu_optics_ThickLens.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 optics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs. Optics/Geometrical Optics/Thick Lens http://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=8257 Sun, 02 Nov 2008 13:12:40 EST http://www.compadre.org/OSP/items/detail.cfm?ID=8257 http://www.compadre.org/OSP/items/detail.cfm?ID=8245 The Ejs Baton Throw model displays a baton thrown up in the air about its center of mass. The baton is modeled by two masses separated by massless rigid rod. The path of the center of mass of the baton and the red mass are shown in black and red, respectively. The ratio of the two masses can be set via a slider and the initial velocity of the center of mass of the baton and the rotational velocity of the baton can be set via text boxes. 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. Ejs Baton Throw 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_mech_cm_BatonThrow.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. Classical Mechanics/Motion in Two Dimensions/Center of Mass http://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=8245 Thu, 30 Oct 2008 11:01:43 EST http://www.compadre.org/OSP/items/detail.cfm?ID=8245 http://www.compadre.org/OSP/items/detail.cfm?ID=8243 The Ejs Rocket Car on an Inclined Plane model displays a car on an inclined plane. When the car reaches the bottom of the incline, it can be set to bounce (elastic collision) with the stop attached to the bottom of the incline. The car consists of the car body, two rotating front wheels, and two rotating rear wheels. The incline angle (in radians) can be changed via a textbox and the rocket’s thrust can be changed via a slider. In addition the car can be dragged to its initial position. 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. Ejs Rocket Car on an Inclined Plane 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_mech_newton_RocketCarOnInclinedPlane.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. Classical Mechanics/Newton's Second Law/Force, Acceleration http://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=8243 Tue, 28 Oct 2008 23:56:21 EST http://www.compadre.org/OSP/items/detail.cfm?ID=8243 http://www.compadre.org/OSP/items/detail.cfm?ID=8242 The Ejs Car on an Inclined Plane model displays a car on an incline plane. When the car reaches the bottom of the incline, it can be set to bounce (elastic collision) with the stop attached to the bottom of the incline. The car consists of the car body, two rotating front wheels, and two rotating rear wheels. The incline angle (in radians) can be changed via a textbox. In addition the car can be dragged to its initial position. 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. Ejs Car on an Inclined Plane 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_mech_newton_CarOnInclinedPlane.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. Classical Mechanics/Newton's Second Law/Force, Acceleration http://www.compadre.org/OSP/bulletinboard/Thread.cfm?ID=8242 Tue, 28 Oct 2008 23:45:15 EST http://www.compadre.org/OSP/items/detail.cfm?ID=8242