Podcast Grades K-5, Are there13+ Planets?

I have viewed a podcast concerning planets. One of the speakers was Director, Neil deGrasse Tyson Director, Hayden Planetarium. He discussed that until August 2006 the International Astronomical Union(IAU), thought they made had made a discovery that there may be 10 or 13 planets instead of 9.

In 1801 a new planet was discovered orbiting between Mars and Jupiter and they called it Ceres. They found more and more planets orbiting the solar system to a number of 13. They decided to stopped counting them and finding names because it was much like finding new real estate outer space called an Asteroid Build. Ceres was then named an asteroid instead of a planet. It was defined by IAU that a planet is a body that orbits the star, a round shape and enough mass to hold its own gravity and orbit. Like Pluto isn't really a planet it's a dwarf planet.

I think it would be cool to have a class activity to illustrate what the Solar System looks like and create new names for the planets and asteroids.