Seafloor Spreading Interactive Animations - Aug 16, 2008

Try UCAR's Seafloor Spreading Interactive Animations for a simulation of the magnetic stripes on the ocean bottom--you can spot them by moving a compass around on a map of the mid-Atlantic Ridge.  For related geophysics simulations from Cornell, see the Plate Tectonics section of Discover Our Earth.

Wave on a String - Aug 1, 2008

In the PhET applet, Wave on a String, you can drag the end of the string up and down to simulate wave motion. To learn more, visit Physic 2000's Standing Waves and Resonance.

PhET: Masses & Springs - Jul 16, 2008

Visit PhET: Masses & Springs for a realistic virtual mass-and-spring lab. You can change variables and see the effect on the motion of the mass. To find out what happens when the mass is driven by an external force, check out Damped Driven Simple Harmonic Oscillator and Driven Harmonic Oscillator.

Magnetic Reversals and Moving Continents - Aug 16, 2008

Magnetic stripes on the ocean floor provide the key evidence for the plate tectonic theory and seafloor spreading. To learn more, visit Magnetic Reversals and Moving Continents and Magnetic Stripes and Isotopic Clocks.

Standing Waves: Harmonics and Patterns - Aug 1, 2008

To find out how two running waves in a tube add up to a standing wave, visit the Physlet applet Standing Waves: A Tube Closed at Both Ends. For a related video, see Standing Wave Movie. For a tutorial on standing waves, with animations, visit Standing Waves:  Harmonics and Patterns.

Simple Harmonic Motion - Jul 16, 2008

In resonance, an applied periodic force makes an object vibrate at its natural frequency. To find out more, visit Hyperphysics: Resonance. To learn about simple harmonic motion, visit the Hyperphysics Simple Harmonic Motion.