Students often have misconceptions about certain science concepts. They occur naturally and they do not happen because a student is not intelligent. The human brain tries to fit information in an easy to digest construct, even though it is not accurate. Misconceptions are very difficult to break. The best way for students to break their misconception is to articulate their understanding and then try confront a demo or new piece of information that contradicts that misconception.
In the video some teachers are asked the question, "What causes the phases of the moon?" They then are asked to demonstrate their thinking and to explain how it works. An explanation and demonstration of how the phases of the moon actually happen takes place in the last third of the video.