Here's an interesting web application that lets you do a keyword search in Flickr and then maps the images with a marker and thumbnail.
What you can do:
* Find a location in the world in a flash.
* Search flickr photos with your desired keywords.
* Explore flickr photos that are taken after a specified date.
* Click on the small thumbnail to enjoy the whole picture.
Perhaps the best use of this tool is to combine the date and keyword search, to track photos streaming into Flickr during or after an event. Should be great for exploring current events in the classroom!
For science class, search for crocus or other phenological indicators and set a start date of February 7 for example.