The EJS 2D Ising model displays a lattice of spins. You can change the lattice size, temperature, and external magnetic field. 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 2D-Ising 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_Ising2D.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.

The 3-D Hydrogen Atom Probability Densitites model simulates the probability density of the first few (n = 1, 2, and 3, and associated l and m values) energy eigenstates for the Hydrogen atom (the Coulomb potential). The main window shows the energy level diagram for the solutions to the Coulomb potential in three dimensions. States may be selected either by using the dropdown menu item or by using the energy level diagram and clicking a dark green level, with specific n, l, and m values) which will turn bright green and change the state shown in the 3d visualization window. The probability is shown with a 3d cloud, with higher probability shown as a darker sphere. The simulation uses either simple 3D or Java 3D (if installed) to render the view the probability densities. If Java 3D is not installed, the simulation defaults to simple 3D using Java. The 3-D Hydrogen Atom Probability Densitites 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_hydrogen3d.jar file will run the program if Java is installed.

Talk FC06 in the "Computational and Online Tools for Teaching Physics" session highlights the Open Source Physics (OSP) community of educators that engage, enable and empower teachers as learners so that we create DIY technology tools-simulation for inquiry learning. We learn through Web 2 online collaborative means to develop simulations together with reputable physicists through the open source digital library. By examining the open source codes of the simulation through the Easy Java Simulation (EJS) toolkit, we are able make sense of the physics from the computational models created by practicing physicists. We will share newer (2010-present) simulations that we have remixed from existing library of simulations models into suitable learning environments for inquiry of physics. We hope other teachers would find these simulations useful and remix them that suit their own context and contribute back to benefit all humankind, becoming citizens for the world.

The EJS Angular Acceleration of a Contracting System model shows a mass and pulley system to illustrate what happens when a rotating system contracts. When the centripetal force has contracted a rotating system to half its initial radius then: (1) The tangential velocity has doubled, (2) The angular velocity is 4 times faster, (3) The rotational kinetic energy is 4 times higher. (4) The required centripetal force is 8 times stronger. 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. The Angular Acceleration of a Contracting System 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_nl_teunissen_angular_acceleration.jar file will run the program if Java is installed. Additional information about this model can be found by visiting the author’s web site: http://www.cleonis.nl/index.htm.

The Ball in a Wedge model displays a ball confined to move between two walls that form a wedge shape. The ball undergoes elastic collisions with the walls of the wedge. The angle of the wedge can be changed by setting the angle with the text box or dragging one of the wedge walls. By clicking in the Poincare section you can set the initial conditions of the motion of the ball. 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 Ball in a Wedge 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_chaosWedge.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 Newtonian mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

The EJS Ballistics and Orbits model displays ballistic trajectories near the Earth. The model shows the trajectory with respect to the inertial coordinate system and the trajectory as seen from a point of view that is co-rotating with the Earth. 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. The Ballistics and Orbits 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_nl_teunissen_ballistics_and_orbits.jar file will run the program if Java is installed. Additional information about this model can be found by visiting the author’s web site: http://www.cleonis.nl/index.htm.

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.

The Blackbody Radiation: Frequency and Wavelength model simulates the blackbody radiation curves of Planck both as a function of frequency and as a function of wavelength to allow for comparison of the two functions. The Planck radiation law can be derived both as a function of frequency and as a function of wavelength. In doing so, one gets two slightly different expressions for the energy density per frequency (wavelength) as a function of frequency (wavelength. Shown in the main window is a schematic of a blackbody cavity showing (on the right) the color of the radiation emitted. The graph plots the energy density per frequency (wavelength) as a function of frequency (wavelength and shows the visible spectrum. One can switch between the two functions by using the radio buttons provided. A slider alows the twmperature to be set or changed. The Blackbody Radiation: Frequency and Wavelength 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_blackbody_fw.jar file will run the program if Java is installed.

The Ejs Celestial Globe model simulates the Two Sphere Universe theory of the Ancient Greeks. This theory supposes the stars to be fixed on the surface of a Celestial Sphere, with the spherical Earth at the center of this sphere. The simulation shows the motion of Sun and stars in this model, as well as the horizon plane for an observer on the spherical Earth. Two views are shown: one from outside the Celestial Sphere, and the other from the point of view of an observer on Earth looking up. Most of the characteristics of the simulation can be adjusted, including the period of Sun's motion, the tilt of the ecliptic relative to the equator, the latitude of the observer, the time of day and the time of year. Ejs Celestial Globe 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_astronomy_CelestialGlobe.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 astronomy are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

The EJS Cellular Automata (Rule 90) model displays a lattice with any one of a finite number of states which are updated synchronously in discrete time steps according to a local (nearby neighbor) rule. Rule 90 is a specific nearby neighbor rule following the classification scheme developed by Stephen Wolfram that produces a Pascal triangle mod 2 (Sierpinski gasket) if there is a single initial cell with a value of one. 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 Cellular Automata (Rule 90) 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_ms_explicit_Automata1DRule90.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.

The EJS Cellular Automata Rules Model shows a spatial lattice which can have any one of a finite number of states and which are updated synchronously in discrete time steps according to a local (nearby neighbor) rule. You can change the lattice size, pick different rules (0 to 255 as classified by Stephen Wolfram), and choose different initial starting conditions (toggle a cell on and off by clicking on a lattice site). 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 Cellular Automata Rules 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_ms_explicit_Automata1DRules.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.

The Authoring Curricular Material Chapeter of the OSP User’s Guide describes Launcher and LaunchBuilder and shows how these programs are used to author, organize, and run Java-based curricular material. In order for most instructors to use OSP material in their courses (or in their educational, experimental, or theoretical research), the various physical models already available must be easily accessible, modifiable, and distributable. The paradigm for authoring, organizing, and running curricular material described in this Chapter uses the Launcher and LaunchBuilder programs to accomplish this goal.

The EJS Coin Flip Equilibrium model simulates a a simple system of N coins arranged in ordered rows. The coins all begin heads up. At each step of the simulation one or more coins are chosen at random and flipped over. Separate windows show the set of coins, a plot of the number of heads/tails after each step, the entropy of the system after each step, and a histogram of the occurrences of a given number of heads. The user can change the number of coins and the number of coins flipped at each step of the simulation. A user can modify this simulation if EJS is installed locally by right-clicking within the plot and selecting "Open Ejs Model" from the pop-up menu item. EJS Coin Flip Equilibrium 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_CoinFlip.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.

The Complex Function Plot program displays a user-defined complex function of position and time using representations that map phase into color. The default complex function is a time-dependent complex Gaussian and the representation can be changed by selecting a radio button. Additional parameters can be specified using the Display | Switch GUI menu item. Complex Function Plot is an Open Source Physics program written for the teaching of mathematical methods in the sciences. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the math_complex_function_plot.jar file will run the program if Java is installed. Other mathematical methods programs are also available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Math.

The Compton Effect model simulates the the scattering of light off of an electron, the Compton effect. Compton used the idea that light behaves like a particle to explain light-electron (photon-electron) scattering. He used the relation for the energy and momentum of the photon and the relativistic expression for the energy of the electron, and applied relativistic energy and momentum conservation for the collision. The wavelength shift of the light depend on the angle of the scattered photon (and the electron). By changing the scattering angle in the simulation, the angle of the scattered photon changes according to Compton's equation. The panel on the left shows the experimental set up, while the panel on the right shows the resulting photon wavelength from the scattering. In a typical Compton experiment, light is scattered off of the electrons in an atom, and there is little scattering due to the more tightly held electrons while there is more scattering due to the less tightly held electrons. This is what is responsible for the two peak distribution shown. The Compton Effect 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_compton.jar file will run the program if Java is installed.

The Ejs Copernican System model illustrates Copernicus' system of planetary motions. The entire system is centered on the center of Earth's uniform, circular orbit. Sun is placed near, but not at, this center point. The orbit of each planet (other than Earth) consists of a deferent circle, centered on a point some distance from the center (at the eccentric point). Attached to this deferent is the center of a much smaller circle, the epicycle (or epicyclet). The radius of the epicycle is 1/3 the eccentricity of the deferent. The planet moves along the epicycle at a constant angular speed equal to twice the angular speed along the deferent. This model produces retrograde motion and changes in brightness that are always properly correlated with the location of Sun. In this simulation, the planet is assumed to move in the plane of the ecliptic, so its latitude is always zero. 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 Copernican System 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_astronomy_CopernicanSystem.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 astronomy are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

The EJS Coulomb's Law and Electric Field Package is a collection of models for electrostatics. Users can move charges around and see the force, observe the electric field generated by charge configurations, and observe the motion of test particles in electric fields. Also included are student worksheets in pdf format to supplement each simulation. Users can inspect and modify any simulation in the package by right-clicking within the plot and selecting “Open Ejs Model” from the pop-up menu item. The Coulomb's Law and Electric Field Package 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_electric_sampler.jar file will launch the package if Java is installed. Navigate within the package and click on a green triangle to run a particular simulation. 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.

The Demo package is a self-contained file for the teaching of orbits, electromagnetic radiation from charged particles and quantum mechanical bound states. The file contains ready-to-run OSP programs and a set of curricular materials. One can choose from several preset examples from each of the three areas of physics contained in the package. The Demo package is an Open Source Physics curricular package written for the teaching of advanced physics topics. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the osp_demo.jar file will run the package if Java is installed. Other curricular packages are also available. They can be found by searching ComPADRE for Open Source Physics, OSP, Orbits, Radiation, or Quantum Mechanics.

The Ejs Dirac Delta Scattering model displays the time evolution of a plane wave incident on a Dirac delta function barrier. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_DiracDeltaScattering.jar file will run the program if Java is installed. The default wave function shows a right-moving plane wave incident on the barrier. The energy of the wave function can be changed with the 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 Dirac Delta Scattering model was created using the Easy Java Simulations (Ejs) modeling tool. 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.

The Double Pendulum model displays the motion of a two-part pendulum and its Poincare map. A double pendulum is a simple pendulum with another pendulum attached to its end and the state of this dynamical system is specified by two angles and two angular velocities. Because there is no friction, the double pendulum is an example of a Hamiltonian system and energy is conserved. This EJS model simplifies the system by using equal length arms and masses. Clicking in the Poincare section sets the initial conditions of the rotor. The user can examine and modify this simulation if EJS is installed by right-clicking within the plot and selecting “Open EJS Model” from the pop-up menu item. The Double 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_lagrangian_DoublePendulum.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.