Stop Motion Animation is a great educational tool. Here is a way you can have students do this on a Chromebook.
1. I suggest one of the IPEVO document camera's. I have one in the IT office that I am willing to lend out.
2. Go to http://www.gifpal-edu.com to get started creating your stop motion animation. You have the ability to do onion skinning, or annotate over the frame, but there is a limit of 48 frames per gif.
3. The gif file can be imported into Wevideo if you want to add audio or combine several gifs together to make a longer video than 48 frames.
Here is the end result: