"So Many Moons" - When Mindy is concerned that the possible addition of a younger sibling to her family might be a challenge, Jet says imagine having a family with more than 60 siblings! That's what it's like for the 67 moons of Jupiter. Curriculum: Kids may think that a planet would only have one moon, maybe two. But the larger outer planets, the gas giants, have many moons - Jupiter and Saturn leading the count with more than 60 moons each! What's more, the moons of Jupiter are not all just round, gray rocks - they are extremely varied, from volcanic Io, covered with volcanic activity; to Europa, with an icy surface covering an underground ocean; to Ganymede, a moon so large it's actually bigger than the planet Mercury! "Project Pluto" - When Mindy is excited about presenting her kid model of Pluto for school show and tell, the other kids don't want to disappoint her by breaking the news to her that Pluto is not a planet. Curriculum: Pluto is no longer considered a planet; astronomers in the scientific community re-classified Pluto as a planetoid. It is one of five "planetoids," or "dwarf planets. There are three criteria a celestial body must meet in order to be considered a planet: it must orbit the Sun, have enough mass, and "clear the neighborhood."