Ducksters
Ducksters: Physics for Kids: Simple Machines
Kids learn about the science behind simple machines such as levers, wheels, pulleys, inclined planes, and screws. How they work together to make complex machinery.
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...