I watched the video podcast entitled "What is A Planet?" I was surprised to find out that up until very recently, scientists had not defined within scientific terms what a planet actually was. This created a dilemma when faced with the amazing new discovery of a possible planet in 2005. But, in 2006 a planet was officially defined in by the International Astronomical Union(IAU) as a celestial body that is in orbit around the Sun, has sufficient mass to assume hydrostatic equilibrium(is a round shape), and has cleared the neighbourhood around its orbit. According to this definition, the planet we know as Pluto is actually considered a "dwarf planet". However, science is constantly changing with new observations and discoveries being made every day. Who knows how many planets there are? Nobody knows for sure, it's mostly speculation that still must be proven.
This video was very educational in that it gave the official scientific definition of a planet. It also showed some computer illustrations and diagrams of the planets in our solar system. This would be a great video to show to my future students, for example during a science class. It's a good way for them to get a visual idea of what our solar system might look like, and what qualifies a planet. I can also imagine the videos being more interesting and engaging for elementary students than, say a textbook would be. "What is A Planet?" showed three dimensional movement in space, as well as interviews with real scientists and astronomers.
Another great aspect to incorporating iTunes podcasts and videos into teaching and education is that the information is condensed. You get a brief, overall, to-the-point review, definition, and explanation of whatever material you are looking at. This gets rid of a lot of excess and/or unneccessary information that would possibly allow the students more opportunities to become distracted. As an added bonus, the videos on iTunesU are free!