Cornell University
Cornell University: How to Build a Cloud Chamber
A very interesting site by university physicist Andrew Foland on how to build a cloud chamber. Includes all the how-to-build information and a materials list as well as a discussion of how to use the cloud chamber and what you should see.
Other
Chemistry Is Easy!: How Do You Write Electron Configurations?
With the goal of making chemistry understandable, this site guides the learner through electron configurations with layman's terms, colorful illustrations, and questions to check learning along the way. The "Purney Cheer" is also...
CK-12 Foundation
Ck 12: Physical Science: Electron Cloud Atomic Model
[Free Registration/Login may be required to access all resource tools.] Features the electron cloud atomic model and atomic orbitals.