If you show a video you need a video question sheet.
Videos are cool...unless you pick one that sucks. Don't do this to kids.
Video Sheet. You decide on how long. Maybe you will only have 3 questions or you might have 30. If you don't have a sheet, many students may stop paying attention. Make sure to have a question for the very end of the video, even if you have to make a fake question up. I recommend you have several reflection/summary questions including WHAT'S THE MOST INTERESTING THING YOU LEARNED IN THIS VIDEO?
Make sure the video you show is worth the time... and not just filling time.
I suggest you make the video sheet 1/2 page if it is a an informative video like a Bill Nye show. Tape the video sheet in their notebook. If you need to verify they did it then walk around with a clip board and check it off.
As a kid I LOVED VIDEOS! Okay, they were MOVIES in my day. I learned things really well in that format. I wouldn't read anything, rarely do my homework and often was clueless about what the teacher was doing...BUT I FOCUSED 100% ON THE MOVIES. I think a lot of kids are the same way.
Hope this helps,
Love to Teach and Teach with Passion
Remember...It's not Magic, It's Science