A satellite flyover of the San Francisco area is a good example of an effective use of images/movies on the Internet. If you click your mouse pointer on the image you can download the movie to your desk top and play it with one of several movie players.
Sound and Animation can be combined. Click on both the audio (ear) and movie (piece of film) icons for the First Step. When you see the small icon of a tape player, click on the triangle. At the same time, click on the film icon. Sound and animation are not coordinated at this site. An example of coordinated audio and visual is given on a flyby of the 3-D ship Ocean Expeditions.
Take a look at some of the National Park QTVR films.
Think of having a set of these movies to illustrate "classic" field trip localities or perhaps you want to let someone tour your office.
Suppose that you wanted to collect information from individuals visiting your site. You could build in an e-mail message form and have the readers sent their response to: jbutler@uh.edu.
This would work OK for a simple request but suppose you had a number of questions that you wanted answered. CGI or the Common Gateway Interface, allows you to build a set of questions, send the questions to your server, and have the server process the information. For example, you might want the data entered into a database. Or, you might allow the user to request certain information from your database.
The Department of Geosciences maintains a short form for prospective students. This form is designed to be sent to the Department in a format that can be read into a tab-delimited database.
An excellent use of forms is given by Virtual Earthquake which is a site all Real or Virtual Seismologists should be aware of.
Although not difficult to do, writing CGI script is where I draw the line. I believe that this is something that should be done by "experts". Otherwise, you could create a problem for yourself or for your organization.
Applets are fully functioning applications which are downloaded to your browser (you should use a recent version) which allow the user to interact with the application. No additional software is needed. The following examples should convince you of the power of these Internet distributed applications.
I remember spending several hours plotting histograms of a set of chest measurements of Scottish soldiers. The point was to see the influence of the sampling interval -- bin width -- on the "appearance" of the histogram. I recall that most of the effort was spent drafting rather than thinking. This histogram of eruption times for Old Faithful allow the user to change the bin width by dragging the icon beneath the histogram.
Or, perform a dice rolling experiment to study the Central Limit Theorem.
The Geophysics Department at Clausthal, Germany, has published two java applets that they have developed to introduce Seismology and 2-D Magnetics. Additional examples are at the GeoJava Corner.
No consideration of the power of Java would be complete without an examination of the Colorado School of Mines exercise on Locating Tunnels.