Elicit non-trivial dialogue from students. Guide students to reflection and analysis of the experience. Encourage students to share their perceptions and beliefs. Summarize and review similarities and differences.

Discussion of experiences.

Objective: To pool observations. To discuss the factors which may affect the way that a tree grows and, thus, alter the color and form of the rings.

Activity: Groups share their time lines and explain why they placed pins at certain points for important events in the life of the tree.

Assessment: Quality of the discussion. Were the students involved in the discussion? How many ideas were generated? Did the students honor each other?