While at Reed High School for the last 14 weeks I noticed that almost on a daily basis History/Social Studies teachers showed historical films and documentaries and/or clips on
a regular basis.

I wonder how much the students are learning from these videos.?!

Since many of the student do not like to read, it may be better than the alternative.

One question I have is: is learning improved by giving background information before showing the video? Or is does increase if the factual information is given after the video?

I don't know.