There are essentially two types of planets in our solar system. The four inner (terrestrial) planets consist mostly of solid rock. The four outer planets are gas giants, consisting of thick outer layers of gaseous materials, perhaps with small rocky cores.
The student will investigate and understand the characteristics of Earth and the solar system. Key concepts include a) position of Earth in the solar system; b) sun-Earth-moon relationships (seasons, tides, and eclipses); c) characteristics of the sun, planets and their moons, comets, meteors, and asteroids; and d) the history and contributions of space exploration.