Time lapse photography

I ran across this blog post and revisited time lapse photography...like one reviewer said it would be really nice if you could import old pictures from the camera roll.  However, this blog brought up another idea on how to use this app in the science classroom.  I love the idea of documenting procedures or construction projects especially since engineering is such an integral part of the science inquiry process now.  This building the bridge assignment (or similar engineering feats) could be documented through this process.  Now without an iDevice to play with, I am not sure how this works whether you can set a timer or whether you have to manually take each picture.  My guess is you can do both.  Be sure to check out the blog entry to gather more info and see an example.