These sites contain material that is generally free to use, uncopyrighted, whose copyright has expired, or is uncopyrightable. The last includes resources from US government agencies, educational organizations and companies that provide materials for students and teachers.
The BBC has excellent educational games, activities, and resources. The BBC Science Clips are a collection of science related activities and games for students who are 5 to 11 years old. Students can grow virtual plants, experiment with pushes and pulls, hearing and sound, forces and movement, electricity, rocks and soils, simple machines, light, solids and liquids, friction, habitats, life cycles, changing states of matter, reversible and irreversible changes, forces, and much more.