In the second step (D: Discuss), it is wanted the students to discuss in your group to share their ideas in own group and to ponder together. In the third step (E: Explain), students in each group are asked to reach a mutual solution about phenomenon and to give their result to other groups through whole-class discussions. Afterwards, the students worked in groups perform hands-on experiment and record individually their observations what happened. In this step (O: Observe),
the students observe changes in the phenomenon and teacher should guide them to make observations that are relevant to target concepts. In the fifth step (D: Discuss), the students are asked to reconcile their predictions with their actual observations made in the early step. Here the students were asked to analyze, compare, contrast and criticize their classmates in the groups. In the last step (E: Explain), the student confronts all discrepancies between observations and
predictions. Doing these, the students begin to resolve the contradictions that may exist between their beliefs. A sample PDEODE teaching activity sheet containing the six steps mentioned above was presented in Figure 1.