My wife has come through again, finding two more great science resource sites.
The first is Science Index which contains links and resources for all different areas and levels of science. Topics include space, natural hazards, weather, health and nutrition, human body, environment, physics, chemistry, biology and more. The resources are grouped by subject area and include lessons and activities.
The second one is Science at PPPST which has PowerPoints, activities, games, and experiments listed by science topic.
Both sites are great resources for anyone teaching science.