The majority of these virtual demos and lab activities originated from explorelearning.com and San Fransisco's Exploratorium. You are encouraged to click around and investigate. Some new additions come from the JavaLab at the University of Oregon.  For most of these you will need a java enabled browser or shockwave. 

Vision and Perception

Waves

Projectiles

Momentum and Collisions

Forces and Newton's Laws of Motion

Roller Coasters (PE and KE)

Reflection and Refraction

Kinematics

Electricity

Chemistry

Buoyancy