How To Make Your Own Volcano

Here's a document on how to make your own volcano. Here's the video on the same topic (youtube.com).

Exploration Through Time

This University of California - Museum of Paleontology web site contains a series of interactive modules that explore the history of life on Earth, while focusing on the processes of science. Each module contains suggested lesson plans and an extensive teacher’s guide.

There's one module that's very good for teaching geologic time.