American Chemical Society
Middle School Chemistry: Chapter 3: Density
Six interactive chemistry lessons about density complete with handouts and animations.
Other
Food and Water Watch: Factory Farm Map
A United States map showing density levels of animals raised for food, accompanied by effects of factory farming and latest news on farming, animal welfare and food safety.
NOAA
Noaa: National Ocean Service: Education: Currents
Illustrated tutorial explains the numerous factors which shape ocean currents. Animations help students visualize how these aspects constantly affect the water movement in the ocean and how scientists use this information to study ocean...
My Science Site
Life Systems: Cells, Tissues, Organs
Extensive site for teachers provides some helpful resources that pertain to plant and animal cells. Includes a microscope diagram as well as plant, animal and pond labs. Also contains links to structures and mechanisms, matter and...