[Free Registration/Login may be required to access all resource tools.] Presents the classifications of igneous rocks based on silica content.

[Free Registration/Login may be required to access all resource tools.] Describes the features of intrusive and extrusive igneous rocks that cool slowly and rapidly, respectively.

Visit an active volcano site to find out the connection between the movement of the Earth's plates and the processes deep within the Earth's interior. [58:23]