Ejs

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...

The Ejs Wave Function Plotter model displays a one-dimensional wave function u(x,t) depicting a disturbance at position x and time t. The disturbance can be mass density, pressure, or electric field depending on the physical context. The default wave function is sinusoidal but any other analytic...

The Ejs Hard Sphere Gas model displays a three-dimensional (ideal) gas made out of hard disks. Particles are initialized with a random speed and in a random direction and move with constant velocity until a collision occurs. You can modify this simulation if you have Ejs installed by...


Platforms: Mac

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...


Platforms: Mac

The Ejs Free Fall model displays the dynamics of a ball dropped near the surface of Earth onto a platform. The initial conditions for the ball are zero initial velocities in the x and y directions. The coefficient of restitution for the ball's collision with the platform is less than one. The...


Platforms: Mac

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...


Platforms: Mac

The Ejs First Law model displays the dynamics of a ball subject to no net force. The initial conditions for the ball are an initial velocity in the x and y directions. The initial position of the ball can be changed by dragging it when the simulation is paused. You can modify this simulation if...


Platforms: Mac

The EJS Kac Model simulates the relaxation of a gas to equilibrium by randomly selecting and then colliding gas molecules but without keeping track of the molecules' positions. As long as the collisions are consistent with spatial isotropy, the Boltzmann speed distribution will emerge. You can...


Platforms: Mac

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...


Platforms: Mac

The Ejs N-body Orbits model displays the dynamics of three to five identical masses orbiting each other subject to Newtonian gravity. The simulation displays the periodic orbital motion of the masses. The initial configuration of the system can be changed via slider. You can modify this...


Platforms: Mac

The Ejs Doppler Effect model displays the detection of sound waves from a moving source and the change in frequency of the detected wave via the Doppler effect. In addition to the wave fronts from the source a graph depicting the time of emission and time of detection of each of the wave fronts...


Platforms: Mac

The Ejs Circumnavigating Pendulum model displays the dynamics of a mechanical oscillator in uniform circular motion. The mechanical oscillator is free to move in two directions. This 2-dimensional simulation displays all the dynamical features of the Foucault pendulum, except for the dependency...


Platforms: Mac

The EJS Radioactive Decay Model simulates the decay of a radioactive sample using discrete random events. It displays the number of radioactive nuclei as a function of time. You can change the initial number of nuclei and the decay constant as well as changing the plot to a semi-log plot. The...


Platforms: Mac

The EJS Magnetic Bar Field Model shows the field of a bar magnet and has a movable compass that reports the magnetic field values. The bar magnet model is built by placing a group of magnetic dipoles along the bar magnet. You can modify this simulation if you have Ejs installed by right-clicking...


Platforms: Mac

The Ejs Phase Space Plotter model displays the dynamics of an ensemble of pendula or simple harmonic oscillators in phase space (velocity versus position). Friction is initially set to zero but can be changed via a textbox as can the number of elements in the ensemble. For the pendulum ensemble,...


Platforms: Mac

The Ejs Hard Disk Gas model displays a two-dimensional gas made out of hard disks. Particles are initialized with a speed v=1 in a random direction and move with constant velocity until a collision occurs. You can modify this simulation if you have Ejs installed by right-clicking within the plot...


Platforms: Mac

The Ejs Lagrange Top model displays the motion of a heavy symmetric top under the effect of gravity. The top has an initial angular speed that provides the precessional, nutational, and rotational speeds. The ratio of Lz to Lx can be set via slider and the initial angular position and angular...


Platforms: Mac

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,...


Platforms: Mac

The Ejs Foucault Pendulum model displays the dynamics of a Foucault pendulum. The simulation is designed to show the dynamical explanation of why precession of the Foucault pendulum is slower at lower latitudes. The simulation shows simultaneously the motion with respect to the inertial...


Platforms: Mac

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....


Platforms: Mac