First, read What is a Geode ? and then read the author's story of her first visit to a geode bed. Once students have realized how a geode is made, and where they can be found, we suggest dividing the class into groups based on the number of geodes you received in your Camp Expedition Kit.
With a small hammer, have one student in each group very gently tap the small geode ball and it will split open - probably in several pieces. You can then pass the pieces around among the group, and let the students examine the geode crystals. On a sunny day, make sure they get the crystals into direct sunlight so they can see the refraction of the light through the crystals. If you have a magnifier, examine the shapes of the crystals. Please have them post a message to the listserv - firstname.lastname@example.org - to report on what they found inside the geode. It is possible there may be geodes that are empty inside. We hope that at least one of the geodes your received will contain crystals, and possibly all of them will.
What is a Geode ?
A Rockhound's First Discovery