They will observe that planets farther away from the Sun have orbits much larger than Earth's. They will also learn that these outer planets move more slowly in their orbits than Earth does. By measuring the model orbits, students will find that Amelia's next destinations are Uranus and Neptune. Concept Orbits are larger when a planet is farther from the Sun. Orbital speed is slower when a planet is farther from the Sun.
Skills Use a scale model to compare orbit sizes for the planets.
Lesson 9 Getting Ready PART ONE 1. Use the permanent marker to draw a line from the center of the plates to the outer rim. Attach the plates to meter sticks at the 1 cm mark with the push pins. For the outer planets, you will have to attach the plates at less than 1 cm. The plates should be secure but still turn freely.