NASA
Nasa Space Place: What Is an Earthquake?
Discover why earthquakes happen, how we measure them, and why they only happen on Earth.
abcteach
Abcteach: Earth
[Free Registration/Login Required] Ready made worksheets for any earth science unit on water cycles, the layers of the earth, or volcanoes.
The Tech Interactive
The Tech: The Core of the Matter
Use this website as a great introduction to one of the basic parts of the inside of the earth, the core. Also provides a short description and cross-section of the Earth.
The Franklin Institute
The Franklin Institute: Earth Bowl
This activity from The Franklin Institute demonstrates the layers of the earth using gelatin, pudding, graham crackers, and a few other items. The learners actually construct a representation of the earth that they can eat.