University of Colorado
University of Colorado: Ph Et Interactive Simulations: Masses & Springs
Hang various mass weights on spring scales while you adjust the spring stiffness and damping in this online activity. Slow down the action, take it to another planet, or watch the amount of potential, thermal, and kinetic energy.
TeachEngineering
Teach Engineering: Attack of the Raging River
In this activity, the students will discover the relationship between an object's mass and the amount of space it takes up (its volume). The students will also learn about the concepts of displacement and density.