Great piece on NPR with Rob Pegoraro from the Washinton Post, who takes the Kindle to the pool and compares the Kindle’s durability to a cell phone. Those definitely go to the pool, and sometimes, in. He doubts the Kindle would survive immersion, and so do I.
But with the drop test in mind, I think that the Kindle would likely survive well in the classroom. Students actually have a good track record of taking care of materials and equipment that is valuable and that they value. The Wifi is the most likely problem with the Kindle in class.