How I Use It
The best way to use these videos is to capitalize on the brief mistakes and misconceptions (often quickly corrected by Mr. Khan) that surface as he thinks aloud in the videos. In teaching gravity, I would use the series of videos as a supplement to classroom instruction, but only after tasking students with watching them with a critical eye for misconceptions or mistakes that Mr. Khan may be making. This would allow students to engage in the meta-cognitive work of noting where they themselves may be struggling. Encourage students to read the question section as well as the “tips and comments” sections of the videos: users to the site post the most useful and interesting YouTube clips and links that are almost more beneficial than the Khan Academy videos. Students also could present answers to those questions in class. The videos certainly reiterate the basic concepts, so these videos are ideal for helping students memorize the basic concepts of gravity and ensure that they understand that a brick and a feather will hit the ground simultaneously in a vacuum.
For teachers seeking to reinforce the concepts of Newton’s law and general understandings of gravity, these videos are a nice supplement to classroom instruction and practice. Be aware, however, that Khan is somewhat imprecise (sometimes using the term “weight” when he means “mass,” for example.). In addition, Mr. Khan sometimes uses examples that may confuse students new to the concepts. In the first video in the series, for example, Mr. Khan begins by discussing rain falling to earth to get students thinking about objects falling towards earth and why that might be. This is a common pedagogical move, however, he gets tripped up in the concept of water vapor thus providing a moment of confusion for students. For students seeking to clarify their understanding of the concepts, be aware that some of the looseness with terms and confusing examples may cause misconceptions to be solidified rather than clarified. Nonetheless, students with a classroom teacher to reinforce terms and concepts may find the numerous examples and working through equations useful.