Peta Todd Model
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
License: Freeware | Size: 1.34 MB | Download (37): N-body Orbits Model Download |
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
License: Freeware | Size: 1.41 MB | Download (35): Doppler Effect Model Download |
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
License: Freeware | Size: 10.24 KB | Download (43): Circumnavigating Pendulum Model Download |
The Rectangular Well model displays the 2D energy eigenstates of a particle trapped in a very deep two-dimensional rectangular well. Because the Schr?*A*dinger equation for this system is separable into one-dimensional infinite square well Hamiltonians, the solution can be expressed as a product...
Platforms: Mac
License: Shareware | Cost: $0.00 USD | Size: 737.28 KB | Download (36): Rectangular Well Model Download |
The Rocking Semicircular Hoop model shows the dynamics of a simple object rocking without slipping on a horizontal surface. It is a supplemental simulation for an article by Leaf Turner and Ari Turner "Asymmetric rolling bodies and the phantom torque" in the Am. J. Phys. 78, 905 (2010). The...
Platforms: Mac
License: Freeware | Size: 785.41 KB | Download (37): Rocking Semicircular Hoop Model Download |
The Ejs Orbiting Mass on a Table 3D model displays the frictionless dynamics of two masses that are attached via a string through a hole in a horizontal table. Mass m moves on the table in two dimensions while mass M hangs vertically and just moves up and down. The simulation allows displaying...
Platforms: Mac
License: Freeware | Size: 1.67 MB | Download (40): Orbiting Mass on a Table 3D Model Download |
The Ejs Driven Diatomic Oscillator Chain model displays a one-dimensional diatomic chain of coupled harmonic oscillators with one end driven by an external force and the other end attached to a sliding rod shock absorber. The mass and Stoke's Law damping for the shock absorber are chosen to...
Platforms: Mac
License: Freeware | Size: 1.18 MB | Download (37): Driven Diatomic Oscillator Chain Model Download |
The Heating and Cooling a Cylinder model computes the radial temperature distribution within a long cylinder as it is heated and cooled by a surrounding fluid. The cylinder is broken into shells and the temperature of each shell is computed using a finite difference approximation to the radial...
Platforms: Mac
License: Freeware | Size: 10.24 KB | Download (40): Heating and Cooling a Cylinder Model Download |
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 (39): 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 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
License: Shareware | Cost: $0.00 USD | Size: 1.19 MB | Download (37): Hard Disk Gas Model Download |
The Heating and Cooling a Sphere model computes the radial temperature distribution within a sphere as it is heated and cooled by a surrounding fluid. The sphere is broken into shells and the temperature of each shell is computed using a finite difference approximation to the radial heat equation...
Platforms: Mac
License: Shareware | Cost: $0.00 USD | Size: 73.73 KB | Download (37): Heating and Cooling a Sphere 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 |