Salary Slip Model
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
License: Freeware | Size: 92.16 KB | Download (40): Magnetic Bar Field Model Download |
The Ejs Duffing Oscillator model computes the solutions to the non-linear Duffing equation, which reads, x'' + 2?zN*x' - x (1 - x2) = f cos(?Ya*t), where each prime denotes a time derivative. The simulation displays the solution as well as the phase space and Poincare plots, and energy diagram....
Platforms: Mac
License: Freeware | Size: 1.37 MB | Download (39): Duffing Oscillator Model Download |
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
License: Freeware | Size: 1.4 MB | Download (37): Phase Space Plotter Model Download |
The Point Charge Forces in One-Dimension model investigates the electric force that one charged particle exerts on another. It is a very simple representation that promotes understanding of Coulomb's Law in three ways: First, students can set the amount of charge on each particle and view vector...
Platforms: Mac
License: Freeware | Size: 1.37 MB | Download (40): Point Charge Forces in 1D Model Download |
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
License: Freeware | Size: 10.24 KB | Download (38): Lagrange Top Model Download |
The Simultaneity Spacetime Diagram model uses light-trajectories to show the effect of relative motion when observing (recording) events in special relativity. In the default scenario, an explosion (an event) at the center of a right-moving stick occurs at t=0 and the arrival of the explosion...
Platforms: Mac
License: Freeware | Size: 755.71 KB | Download (36): Simultaneity Spacetime Diagram Model Download |
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
License: Freeware | Size: 1.3 MB | Download (36): Molecular Dynamics Model Download |
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
License: Freeware | Size: 1.05 MB | Download (36): Foucault Pendulum Model Download |
The Equatorial Coordinates model displays the position of a star in equatorial (Right Ascension/Declination --- RA/Dec) coordinates. The horizon is shown along with the four cardinal directions (N, E, S, and W). The Latitude slider changes the latitude of the observer which is shown by the change...
Platforms: Mac
License: Freeware | Size: 993.28 KB | Download (36): Equatorial Coordinates Model Download |
The Ejs Inertial Oscillation model displays the motion of a particle moving over the surface of an oblate spheroid. The spheroid is flattened to an ellipsoid of revolution because it is rotating, just as the Earth is flattened because it is rotating. The particle is confined to motion along the...
Platforms: Mac
License: Freeware | Size: 1.05 MB | Download (36): Inertial Oscillation Model Download |
The EJS Equinox Precession model illustrates the Copernican theory of Earth's orbit around the sun. The top window shows a view from outside the celestial sphere. The simulation shows the moving Earth along with its axis or rotation and the line of sight from Earth, through Sun, to the Celestial...
Platforms: Mac
License: Freeware | Size: 1.32 MB | Download (36): Equinox Precession Model Download |
The Ejs Coin Rolling without Sliding on an Accelerated Platform model displays the dynamics of a coin rolling without slipping on an accelerated platform. The simulation displays the motion of the coin as well as the velocity vectors for the surface of the coin and the platform. The initial...
Platforms: Mac
License: Freeware | Size: 1.33 MB | Download (36): Coin Rolling without Sliding on an Accelerated Platform Model Download |
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...
Platforms: Mac
License: Freeware | Size: 1.38 MB | Download (36): Damped Driven Harmonic Oscillator Phasor Model Download |
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
License: Freeware | Size: 1.34 MB | Download (37): Quartic Oscillator Model Download |
The Ejs Normal Modes on a Loaded String model displays the motion of a light string under tension between two fixed points. The string is also loaded with N masses located at regular intervals. The number of masses on the string can be changed via textboxes. You can modify this simulation if you...
Platforms: Mac
License: Freeware | Size: 1.35 MB | Download (40): Normal Modes on a Loaded String Model Download |
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...
Platforms: Mac
License: Freeware | Size: 1.43 MB | Download (41): Strange Harmonic Oscillator Model Download |
The Driven Mass and Spring Mesh model displays the dynamics of a 2D array of masses coupled by springs and driven by a sinusoidal force. The model shows a time-dependent animation of the displacement or each mass. The driving force can be applied at a single point (shown in red) or uniformly at...
Platforms: Mac
License: Freeware | Size: 1.06 MB | Download (36): Driven Mass and Spring Mesh Model Download |
The Diffraction and Interference Model: Single and Double Slits shows diffraction and interference patterns from a single slit, double sources and double slits. The user can change the source wavelength, slit width, separation and distance between slit and screen. The Diffraction and...
Platforms: Mac
License: Freeware | Size: 808.96 KB | Download (38): Diffraction and Interference Model: Single and Double Slits Download |
The Eratosthenes model displays the shadows cast by two gnomons (sticks) at different locations on Earth. For one gnomon, Sun is directly overhead (as would be the case if the gnomon was on the Tropic of Cancer at the summer solstice). The other gnomon is due north of the first gnomon. The sizes...
Platforms: Mac
License: Freeware | Size: 860.16 KB | Download (35): Eratosthenes Model Download |
The Ejs Waves and Phasors model displays the motion of a transverse wave on a string and the resulting phasors for the wave amplitude. The simulation allows an arbitrarily polarized wave to be created. The amplitude, period, phase velocity and number of phasors displayed can all be changed via...
Platforms: Mac
License: Freeware | Size: 1.32 MB | Download (37): Waves and Phasors Model Download |