Lesson 10: Apply the Models to the Sundial Observations

Maureen Dooley, B.S.Ed.

Copyright 2004. Permission is granted for classroom use and for non-commercial educational purposes.

Subject __________________________

Anticipatory Set (focus) - The students will answer a warm-up question from the board; What direction did the shadow on the sun dial move?

Purpose (objective) -The students will be able to describe the motion of the sundial using both the moving sun model and the spinning earth models. The students will be able to evaluate both models and will conclude that both models work well in explaining the change in the shadow of the sun dial. (There is no right answer; accept arguments for both models)

Input - The teacher will respond to answers to the warm-up question. The teacher will correct, concur or elaborate on the answer as needed. The teacher will explain to the students that they will be divided into two groups of "lawyers". One group of "lawyers" will be arguing the case of "the sundial shadow moves based on the moving sun model". The second group of "lawyers" will be arguing the case of "the sundial shadow moves based on the spinning earth model". They will prepare their arguments in their respective groups and write down; using only the evidence that they have that proves their argument. At the end of the class they will present their arguments to the "judge", the teacher, and the rest of the class.

**(Notes are provided for the teacher for these two models)

Modeling (show) - The teacher will explain what the moving sun model and the spinning earth model to the students, either verbally or in written notes. The teacher will not show preference as to which model is more valid. The teacher will then show the students an example of an appropriate argument. For example we "know" that the sun makes the shadow because we see the shadow cast onto the piece of paper. It should be explained that an argument is not casting accusations and inflammatory remarks at those who hold the opposing view.

Guided Practice - The teacher will ask the students to divide into two groups. One group will be "lawyers" arguing the case that the sundials shadow moves based on the moving sun model. The second group of "lawyers" will be arguing the case that the sundials shadow moves based on the spinning earth model.

Independent Practice - Once the two groups are established the students will use their notes and they will work in their cooperative groups to come up with convincing arguments/facts/opinions that proves that their case for the movement of the shadow is more reasonable. Allow 20-30 minutes to complete this activity. Each student in the group will record all of the arguments so that they have a written record of the activity.

Closure - (Tell or show me what you have learned) - After 20-30 minutes in their cooperative groups the teacher will ask the groups to reveal the arguments they have prepared. The teacher will record on the board the evidence for both arguments and will instruct the students to copy down the arguments from the opposing "lawyers". The teacher will then guide the students into concluding that both arguments are valid, and that by just using the sundials moving shadow we cannot choose the preferred model. They both work as explanations. The teacher will explain that in the next lesson more evidence will be brought forth that will clarify which model works better.