Newton’s Mountain Model - Aug 26, 2009

The EJS Newton's Mountain model illustrates the motion of a projectile launched from the top of a VERY tall mountain on Earth. The diagram shown in the simulation is taken from Newton's A Treatise on the System of the World, which he wrote after the Principia. Newton concluded that a projectile launched horizontally with sufficient speed would orbit Earth rather than crashing to Earth's surface.

Phases of Moon Model - Jul 31, 2009

The EJS Phases of Moon model displays the the appearance of Moon and how it changes depending on the position of Moon relative to Earth and Sun. The main window shows Earth (at the center). By using the Options Menu the Moon View window shows the appearance of Moon as seen from Earth when Moon is in the position shown in the main window.

Great Circles Model - Jan 19, 2009

The Ejs Great Circles model displays the frictionless motion of a particle that is constrained to follow the surface of a perfect sphere.  The sphere rotates underneath the particle, but since there is no friction, and the sphere is perfectly spherical, the motion of the particle is not influenced by the sphere.

QM Eigenstate Superposition Demo Model - Oct 16, 2008

The Ejs QM Eigenstate Superposition Demo model displays the time dependence of a variety of superpositions of energy eigenfunctions for the infinite square well and harmonic oscillator potentials.  One of the eleven pre-set superpositions can be selected via a drop-down menu with the resulting wave function shown in phase-as-color representation.

Platform on Two Rotating Cylinders Model - Oct 9, 2008

The Ejs Platform on Two Rotating Cylinders model displays the model of a platform resting on two equal cylinders are rotating with opposite angular velocities.  There is kinetic friction between each cylinder and the platform.    The separation between the cylinders and the coefficient of kinetic friction can be changed via textboxes.