Many districts understandably block Youtube in schools. For this reason you may want to download videos for classroom use. You can do this from http://www.zamzar.com.
If you need help doing this. Click on this screen capture from Zamzar where I’ve highlighted what you need to do:
Why would you want to do this?
The short film format is perfect for providing an effective unit opener. For example, search for dinosaurs and find some terrific footage that could be used to introduce the fossils unit.