Be a Paleontologist
In the sand table place dinosaur bones, a variety of brushes, magnifying glasses, and some small boxes. Allow children to play in the sand table with minimal adult direction.
Look for clay, silt, sand gravel, pebbles, cobbles and boulders.
http://www.fossweb.com FIND EARTH MATERIALS- Interactive website that has all kinds of interactive science activities showcasing many curricular divisions. LOVE IT!