The document discusses why Pluto is classified as a dwarf planet instead of a regular planet. It explains that Pluto was reclassified in 2006 because unlike regular planets, it has not cleared the neighborhood around its orbit. The document also notes that the planets revolve around the sun in elliptical orbits. Finally, it provides instructions for an activity where students make masks of the sun and planets and act out revolving around the sun like the planets do.