1. ENGAGE:
   There are several ways to engage students in this activity. You could start by showing Virtual Earth, which can be streamed from the the South Carolina Educational TV website or the Apple Learning Interchange to show your students the importance of studying the Earth. This could be followed by the hands-on activity in the Educators Guide or the web activity or both found at the NASA CONNECT web site. Start the GPS Challenge web activity with a story involving Norbert and Zot as world travelers who have a GPS and you should describe how their GPS can determine their location using geometry. Squeak, an engaging multimedia authoring environment, will grab the attention of young learners.
2. EXPLORE:
   Norbert and Zot challenge your students to explore world locations they visit and learn geography. By using the simulated GPS system to locate Norbert and Zot, your students will explore plane geometry ideas relating to intersecting circles. In extension 2 listed below, your students can explore plane geometry further and refine the initial theorem used to locate the position of Norbert and Zot. There are several exceptions to the theorem as stated initially and the process of realizing this and clarifying the original statement is a valuable educational experience. In extensions 3 and 5, your students can explore, compare, discuss, and think about one, two and three dimensions. If you choose to do the extensions involving modifying Squeak, you can challenge your students to explore how the Squeak GPS Challenge works.
3. EXPLAIN:
   Have your students explain how a GPS can locate their position on the surface of the Earth to the class or to their group. To prepare students for their oral presentation, assign as homework the task to write a short paragraph on how a GPS can locate your position on the surface of the Earth and to include a drawing. For the extensions below, encourage your students to accompany their words with pictures they draw.
4. EXTEND:
   Close this window and follow the link in the Teacher Information area for a list of extensions with ideas ranging from straightforward to very challenging. You can modify the suggested extensions to fit the class time you have available.
5. EVALUATE:
   After the student presentations on how a GPS locates positions the class should discuss the presentations and come up with a common concensus for the process. For the extensions listed above the students should evaluate the conclusions of other students.