Grades K-12 . This site features ten of the most requested teacher created science lessons and activities. Straight forward and easy to use for all grade levels. These are simple, quick, and require minimal equipment. Well worth a look if you need to make a point in a hurry.
Site has numerous related activities and links.
This page is part of a larger energy site. While these experiments appear very useful, the quality of some other sections is spotty. Exploratorium Science Snacks - This site was developed by the Exploratorium Regional Science Resource Center, San Francisco, Ca. They each begin with a photograph, list of materials, background information and procedure. These are well organized and although originally intended for High School, are of value to all levels and can easily be adapted.