by Professor Mark Sutherland, University of Toronto.

http://thorin.adnc.net/~topquark
/fun/JAVA/dho/dho.html

Control the initial amplitude and damping coefficient for a mass attached to a spring. Displacement, velocity and energy versus time are plotted.

Professor Sutherland has a collection of physics applets and tutorials at fun@learning.physics.

by Dan Russell, at Kettering University in Flint, MI .

http://www.kettering.edu
/~drussell/Demos/SHO
/mass.html

One of many excellent animations at Russell's Acoustics and Vibration Animations. This page shows a derivation of the Simple Harmonic Oscillator (SHO) including an animated gif showing the simple harmonic motion of three undamped mass-spring systems.

from the ExploreScience site of Raman Pfaff at the University of Michigan, Ann Arbor.

http://www.explorescience.com
/activities/Activity_page.cfm?
ActivityID=22

In order to use this site you must download and install the Macromedia Shockwave Plug-in on your computer.

This activity allows you to compare a simple pendulum and a simple harmonic oscillator. You can control the mass on each as well as the lengh and spring constant. The really fun part comes with controling the acceleration due to gravity and making it different than Earth's.

by Walter Fendt, Augsburg, Germany.

http://www.walter-fendt.de
/ph14e/
springpendulum.htm

Control the mass, spring constant and amplitude of a mass hung on a spring. Displacement, velocity, acceleration force or energy vs time can be plotted in real time. The applet allows you to experiment and determine the relationship between these variables and the period.

Herr Fendt has a collection of other physics applets on his site.