A. John Mallinckrodt   Professor Emeritus of Physics, Cal Poly Pomona
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This page offers links to interactive simulations I wrote using Interactive Physics™, now from Design Simulation Technologies—once upon a time, Knowledge Revolution.
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Interactive Physics




Previous Page

Most of these simulations are in the old IP Student Version Player format, should be directly usable in the Macintosh Classic environment, and may or may not still be usable in the Windows environment. They were developed in a Macintosh environment and some of the fonts and screen layouts may not translate very well into the Windows environment.

The publisher has discontinued support for the Macintosh environment, a decision I do greatly regret as I have lost what was once my most favored in-class computational aid. Accordingly I no longer support this page, but maintain it as a slowly crumbling monument to better times.

At one time the following information was useful:

The simulations are available for individual download. You might want to configure your browser to launch and view them automatically with your copy of the Interactive Physics™ application program. To do so, you will need to edit your browser preferences. In the "file helper" area, create a new descriptor that tells your browser to link files with the extension ".IP" to the Interactive Physics™ application and, if desired, to open and view them with that application. Following some advice from Richard Vawter at Western Washington University these simulations have been assigned the pseudo-MIME type, "application/x-ip" which you may or may not also need to tell your browser. Professor Vawter maintains an extensive IP web site, which uses the same conventions and is well worth visiting.

Instructional Project

Read Me File

A collection of IP modules and associated worksheets that I am (or at least was) developing for use in the "Newton's Laws" section of my introductory physics course. Includes five IP modules and five associated worksheets as well as three "special assignments" which were administered to a "control" group of students who were not given access to the IP modules.

This is was definitely a work "in progress." Help yourself, but beware!


IP 2.5 incorporated errors in some of its physical formulas and specific behaviors that were fixed and/or altered in IP 3.0 and later versions. For instance, in IP 2.x "kinetic energy" is DEFINED as mv2(!!). Thus, I have had to manually insert a factor of 1/2 into scenarios that use the KE function. As a result, when played with IP 3.0 (in which the KE function has been corrected), these scenarios effectively use the formula KE = mv2/4. Sigh. (It can be fixed—if you know what you are doing—by getting into the appropriate "meters" and editing the formulae. Maybe I will get around to making this whole process a little more transparent at some point!) Not likely!

You can request an evaluation version of Interactive Physics™ from the publisher's website. If you do download the evaluation version and find that it does or does not deal with these simulations I'd like to know about it. If you are primarily a Macintosh user, you might consider adding a few words about Macintosh support in the "Comments" area of the form.)

This page is was continuously under construction. I welcome all comments.

*All the simulations available here are Copyright 1993- by A. John Mallinckrodt. They are free for personal or nonprofit instructional use. For other uses, please contact me.

Mechanics Simulations                    Back to top

Bat'n Ball

Just for fun... A very interesting double collision between a bat and a ball.

A 0.7 MB Quicktime Movie.

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The Driven Harmonic Oscillator

Adjust the drive frequency and restoring force of a driven oscillator and examine the resulting amplitude and phase difference.

A 2.9 MB Quicktime Movie.

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The Energy Widget (IP 5.0)

Just watch as three balls interact elastically with seven pivoted bars and try to find their way out. For people with way too much time on their hands. Kind'a fun though.

A 5.5 MB Quicktime Movie.

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Jerk the String (IP 5.0)

A simulation of a classic physics demo. Illuminates the fundamental difference between pulling on the lower string gradually or quickly.

A 2.0 MB Quicktime Movie.

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Gravitation/Reference Frame Simulations                    Back to top

Lagrange Point

Adjust the mass ratio and orbital eccentricity of the two primary gravitating bodies. Then perturb the orbital speed of a body at L4 (or 5). Explore the stability of the Lagrange point while observing the motion from either the inertial or rotating frame. (Inspired by A.F.Burr)

A 4.6 MB Quicktime Movie.

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Diving in a Rotating Space Station

Adjust the takeoff speed, direction, and rotation of a diver in a rotating space station and examine her trajectory in both the rotating and the inertial reference frame.

A 1.8 MB Quicktime Movie.

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Gravitational Boost

Adjust the flyby speed of a planet and examine the resulting gravitational velocity boost of a satellite.

A 1.7 MB Quicktime Movie.

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Orbital Ensembles

Look at an ensemble of orbits in an inverse r-squared field that have either constant energy or constant angular momentum and see the interesting geometric features that they share.

A 1.4 MB Quicktime Movie.

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Principle of Equivalence

Look at the trajectories of two clusters of projectiles located at two different places on the earth from the reference frame of either 1) the earth, 2) one of the members of the local cluster, or 3) one of the members of the distant cluster.

A 0.8 MB Quicktime Movie.

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Tidal Effects

Look at the time-dependent effects of tidal forces on the apparent weight of a "stationary" object.

A 4.1 MB Quicktime Movie.

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Tidal Forces (IP 5.0)

A planet is attracted to a "Sun" and can fall toward it and/or rotate at various speeds. Meanwhile four people stand on the planet and monitor the relative contact force with the planet. Demonstrates the that tidally induced contact forces are minimal along the line joining the two large bodies and maximal at points equidistant from those points.

A 2.5 MB Quicktime Movie.

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Moon Synch

A "Moon" and an "Earth" each consisting of four bodies attached to each other by adjustable springs and dashpots are given adjustable initial rotational and orbital velocities. The simulation exhibits the tidal drags that slow the moon, lock its rotational phase, and circularize its orbit.

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Quasi-Thermal Simulations                   Back to top

Inelastic Collision

Illustrates the conversion of bulk kinetic energy to internal energy in a collision of an object with a fixed wall.

A 1.7 MB Quicktime Movie.

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Bouncing Ball

Drop a ball consisting of seven "atoms" interacting with adjustable stiffness and lossiness. Watch as each bounce converts bulk energy into internal energy. As the internal energy is dissipated, the bounces die out. Reverse time for an interesting violation of the second law of thermodynamics.

A 3.0 MB Quicktime Movie.

[Caution. This scenario corrects the faulty KE formula in IP2.5 and, therefore, gives improper results in IP3.0 (see discussion above). It can be corrected by going into edit mode, selecting and revealing the hidden meter just below the "ball," and editing out the "/2" that follows the reference to "kinetic()" in the properties window for that meter.]

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Molecular Interactions (IP 5.0)

Observe a variety of effects as a collection of particles interacts with itself and the environment in a very flexible manner. The particles are given an adjustable amount of initial kinetic energy. They interact both via a short range molecular type force with adjustable range and strength and via an electrostatic force with adjustable strength. They are also subject to variable external gravity and damping effects. See the Documentation for more info.

A 1.6 MB Quicktime Movie.

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Molecular Interactions
(neutral system)
(IP 5.0)

A version of “Molecular Interactions” that is optimized for viewing the collective effects due to a neutral molecular short range interaction. Observe evaporation and condensation. See the Documentation for more info.

A 1.5 MB Quicktime Movie.

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Molecular Interactions
(ion system)
(IP 5.0)

A version of “Molecular Interactions” that is optimized for viewing the collective effects due to ion interaction. Observe how energy minimization leads to the spontaneous emergence of crystal structures. See the Documentation for more info.

A 4.2 MB Quicktime Movie. (Starts with a barely stable “buckyball” under electrostatic and hard-shell interactions. Softening the shell—by increasing the range—leads to an electrostatically dominated cubic close-packed structure. Eliminating the electrostatic force leads to a hexagonal close-packed structure. Replacing the intermolecular force with a pure electrostatic force leads to the formation of diatoms. )

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Molecular Interactions
(atomic system)
(IP 5.0)

A version of “Molecular Interactions” that is optimized for viewing interactionsbetween pairs or trios of ions. Watch “atoms” form and be destroyed via collisional deexcitation and excitation. See the Documentation for more info.

A 1.3 MB Quicktime Movie.

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Electrical Simulations                   Back to top

Test Charge

Adjust the magnitude, sign, and location of a test charge relative to an initially uniformly charged sphere and discover why we need to define the electric field in terms of the effects on a vanishingly small test charge.

A 2.0 MB Quicktime Movie.

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Electrostatic Equilibrium (IP 5.0)

Watch a collection of charges come to equilibrium on a conducting disk. Requires IP3.0 or higher.

A 2.3 MB Quicktime Movie.

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Dipole Forces (IP 5.0)

Move a dipole up and down and watch the interaction with another identical dipole suspended from a spring of variable stiffness. Requires IP3.0 or higher.

A 1.8 MB Quicktime Movie.

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Instructional Project                 Back to top
      Read Me File

Module 1
(Push the Puck)

Worksheet 1

Special Assignment 1
(alternate "thinking only" coverage for the material in Modules 1 and 2.)

Push a puck around a frictionless horizontal playing field to develop a quasi-visceral sense of Newton’s First and Second Laws.

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Module 2
(Land the Rocket)

Worksheet 2

The Classic "Land the Rocket" game in which the user fires rockets to attempt to land a rocket safely.

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Module 3
(Pushing Game)

Worksheet 3

Special Assignment 2
(alternate "thinking only" coverage for the material in Module 3.)

A variety of challenges to attempt to control the motion of a puck via a single force. Culminates in a race around a course.

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Module 4
(One-D Motion)

Worksheet 4

Special Assignment 3
(alternate "thinking only" coverage for the material in Modules 4 and 5.)

Apply a one dimensional force to a puck and associate the resulting motion to graphs of position, velocity, and acceleration.

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Module 5

Worksheet 5

Adjust the parameters of a pair of colliding masses and look at the results of a one-dimensional collision.

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©2001 by A. John Mallinckrodt
ajm at cpp.edu


The space for this page is provided by Cal Poly Pomona and is subject to its policies. Nevertheless, the opinions expressed here are my own and do not necessarily represent official policy of the University. I take full responsibility for the information presented and will appreciate being informed of errors or inaccuracies.