Science Education Standards: Standard D3:

Earth in the Solar System

• The Earth is the third planet from the sun in a system that includes the moon, the sun, seven other planets and their moons, and smaller objects, such as asteroids and comets. The sun, an average star, is the central and largest body in the solar system.
• Most objects in the solar system are in regular and predictable motion. Those motions explain such phenomena as the day, the year, phases of the moon, and eclipses.
• Gravity is the force that keeps planets in orbit around the sun and governs the rest of the motion in the solar system. Gravity alone holds us to the Earth's surface and explains the phenomena of the tides.

Short Description: To appreciate the complexity of the solar system requires an understanding that it is a dynamic system -- a system in motion. Objects bound to the sun by gravity -- planets, dwarf planets, comets, asteroids, and trans-neptunian (or Kuiper Belt Objects) -- follow elliptical orbits around the sun. Students first explore the geometric nature of ellipses, and the circle as a special case. These newly developed mathematical skills are then used to plot an accurate model of the outer solar system, which contains the size, eccentricity and orientation in space of the orbits for different classes of objects. Students are then able to understand how orbits can be used to help categorize objects in the solar system.