A small (~10) collection of web-based science activities. Teachers like the site, and I think kids do too. The activities use an inquiry-based approach with high-interest topics to build science skills. Teacher guides are available.
Subscription-based site. Includes exploration-type activities with virtual manipulatives plus assessments (quizzes).
Portal for creating online science projects (I think). Student work can be tracked (I think). Active projects are available for teachers to use (I think).
Some virtual lab tools in topics including biology, chemistry, genetics, evolution, modeling and physics.