National Geographic 101 is a nice series of videos produced by National Geographic. The videos in the series provide short (2-5 minutes) explanations of an array of science topics including space science, geology, and weather. The sample that I have embedded below is Volcanoes 101.
Applications for Education
All of the videos in this series could be used as introductions to their respective topics. None of the videos that I watched were what I would call detailed in their explanations.