Downloadable Flash Animations from David M. Harrison


Adding Two Vectors A simple demonstration of adding 2 vectors graphically. Also demonstrates that vector addition is commutative.
Adding Three Vectors A simple demonstration of adding 3 vectors graphically. Also demonstrates that vector addition is associative.
Subtracting Two Vectors A simple demonstration that subtracting 2 vectors graphically is the same as adding the first one to the negative of the second one.
Adding Vectors with Components A simple demonstration that to add 2 vectors numerically, just add the cartesian components.
Unit Vectors A simple animation of unit vectors and vector addition.
Dot Product A simple demonstration of the relation between the dot product of 2 vectors and the angle between them.
Cross Product The direction of the cross product of 2 vectors is demonstrated. The magnitude shown is correct but not discussed.
Derivative of a Sine Function An animation illustrating that the derivative of a sine function is a cosine.
Integration Illustrating the meaning of the integral sign, including an example.
Area of a Circle as a Limit Illustrating that the area of a circle is a limit of the sum of the areas of interior triangles as the number of triangles goes to infinity.


Displacement and Distance A simple animation showing the difference between the distance and the displacement.
Motion Diagram A car with a non-zero initial speed has a constant acceleration whose value can be controlled by the user.
Constant Acceleration 1-dimensional kinematics of a body undergoing constant acceleration. Includes visually integrating the acceleration and velocity graphs, and visually differentiating the position and velocity graphs.
Racing Balls Two balls roll down two different low-friction tracks near the Earth's surface. The user is invited to predict which ball will reach the end of the track first.
Racing Skiers Same as the above animation except with skiers.
Galilean Relativity Illustrating Galilean relativity using his example of dropping a ball from the top of the mast of a sailboat.
Dropping Two Balls Two balls falling near the Earth's surface under the influence of gravity.
Projectile Motion Firing a projectile when air resistance is negligible. The initial height and angle may be adjusted.
Monkey Hunter An animation of the classic lecture demonstration.
Forces on a Pendulum The weight, force due to tension, and total force exerted on the bob of a pendulum are shown.
Mass Moving in a Vertical Circle A mass is in circular motion in the vertical plane. We show the weight and force exerted by the tension in the string.
Hooke's Law A simple animation illustrating Hooke's Law
Collisions on an Air Track Elastic and inelastic collisions on an air track, with different masses for the target cart.
Rolling Disk A simple animation that traces the motion of a point on a rolling disc.
RHR for Angular Velocity The direction of the angular velocity vector given by a right-hand screw rule.
Precession of a Spinning Top A simple animation of a spinning top which precesses.

Fluids, Oscillations and Waves

Simple Harmonic Motion I Demonstrating that one component of uniform circular motion is simple harmonic motion.
Simple Harmonic Motion II Illustrating and comparing Simple Harmonic Motion for a spring-mass system and for a oscillating hollow cylinder.
Damped SHM The damping factor may be controlled with a slider. The maximum available damping factor of 100 corresponds to critical damping.
Driven SHM A harmonic oscillator driven by a harmonic force. The frequency and damping factor of the oscillator may be varied.
Traveling Waves Illustrating the sign of the time term for traveling waves moving from left to right or right to left.
Standing Waves Explanation A wave is reflected from a barrier with a phase reversal, setting up a standing wave.
Standing Waves - Both Ends Fixed The first three standing waves for nodes at both ends. The frequencies of the waves are proportional to one over the wavelength.
Standing Waves - One Fixed End The first three standing waves for a node at one end and an antinode at the other. The frequencies are proportional to one over the wavelength.
Plane Wave Through Two Mediums Illustrating the relation between wavelengths and frequencies of a wave when it travels from one medium to another.
Pressure and Displacement Waves This animation shows air molecules vibrating, with each molecule "driving" its neighbor to the right. It is used to illustrate that when the displacement wave is at a maximum then the density of the molecules, and thus the pressure wave, is at a minimum and vice versa.
Tuning Fork A small animation of a vibrating tuning fork producing a sound wave.
Beats Illustrating beats between 2 oscillators of nearly identical frequencies.
Physics of Music A very brief introduction to the physics and psychophysics of music, with an emphasis on temperament, the relationship between notes.
Doppler Effect Explanation Illustrating the classical Doppler Effect for sound waves.
Doppler Wave Fronts Illustrating the wave fronts of a wave for a moving source.

Electricity and Magnetism

Electric Field Lines Illustrating representing an electric field with field lines.
E-Field of Oscillating Charge Illustrating representing an electric field with field lines.
Circuit / Water Analogy

A simple DC circuit has a DC voltage source lighting a light bulb. Also shown is a hydraulic system in which water drives a turbine. The two systems are shown to be similar.

Light Switch A simple animation of how a common light Switch works.
Simple Buzzer A simple buzzer consisting of a battery, a flexibile metal strip, a piece of iron, and some wire.


EM Wave A 3 dimensional animation of the "far" fields of an oscillating charge.
Rotating Mirror and Reflected Wave Illustrating that when a mirror is rotated by an angle, the reflected ray is rotated by twice that angle.
Reflection and Refraction Illustrating reflection and refraction, including total internal reflection.
Refraction Explanation

This animation shows wave fronts entering a mediums at a non-zero angle of incidence.

Circular Polarization Circular polarization generated from a linearly polarized electromagnetic wave by a quarter-wave plate.

Modern Physics

Michelson Morley Experiment A simple analogy involving two swimmers that sets up the Michelson-Morley Experiment.
Simultaneity A tutorial that shows how the relative nature of the simultaneity of two events must follow from the existence of length contraction.
Time Dilation A demonstration that the phenomenon of time dilation from the special theory of relativity necessarily follows from the idea that the speed of light is the same value for all observers.
Twin Paradox There are many ways of approaching this classic "paradox". Here we discuss it as an example of the relativistic Doppler effect.
Length Contraction A tutorial that shows how relativistic length contraction must follow from the existence of time dilation.
Pair Production and Annihilation A simple illustration of electron-positron production and annihilation.
Interaction of X-Rays with Matter

Illustrating the 3 principle modes by which X-rays interact with matter.

Bohr Model of Hydrogen

The photon excitation and photon emission of the electron in a Hydrogen atom as described by the Bohr model.

Wave / Particle Duality Here we visualize a hydrogen atom, which consists of an electron in orbit around a proton. In one view the electron is a particle and in the other view it is a probability distribution.
Double Slit Experiment with Electrons The famous "Feynman Double Slit Experiment" for electrons. Here we fire one electron at a time from the electron gun, and observe the build-up of electron positions on the screen.
Bells Theorem Based on an analysis by Mermin, this animation explores correlation measurements of entangled pairs.
Nuclear Decay The decay of 500 atoms of the fictional element Balonium. Uses a proper Monte Carlo engine to simulate real decays