This week for our science fact on caves, you may want to check out these sites for a little visual:
Here's a cool art project based on cave painting!
And check out the American Cave Conservation Association's kids' page.
Similar to our crystal making experiment awhile back, this experiment helps kids understand the formation of stalactites and stalagmites!
And here are a few National Geographic videos exploring Kartchner Caverns, Howe Caverns, and Carlsbad Caverns with a lot of amazing formations and insight into cave ecology—though I have not previewed all these videos. PBS Kids has a cave video, too.