Assignment 3
If Scientists Think...

Adapted from:  What On Earth Is Evolution?  The Geological Perspective of Teaching Evolutionary Biology Effectively,   by Abour Cherif, Jerry Adams, and John Loehr (2000)

Goals:

• To understand the types of thinking and evidence that scientists use to make claims about historical events (prior to humans).
• To know the types of evidence which indicate that the earth is 4.5 billion years old.
• To practice critical thinking skills.

Objectives: Students will

1. Complete the 'If Scientists Think....' worksheet
2. Critically evaluate the responses of their peers
3. Come to a consensus on appropriate answers for each worksheet item.

Scientists have determined the age of the Earth to be around 4.5 billion years.  The earliest hominids, or human-like animals (not even humans yet), have only been around for about the last 4 million years.  Hearing this, any self-respecting independent thinker would have to ask, "If there were no people around to see how and when the Earth formed, how have scientists determined the age of our planet to be so great?"  In this assignment, you will work in both small groups and as a class to discuss this very question.  After finishing this assignment, you will be prepared to begin further investigation into the methods and tools scientists used to arrive at their estimation of the Earth's age.

First, divide yourselves into groups of four individuals.  You may want to use the same group from Assignment 2, or you may want to change the composition of your group for this assignment.  Check on group assignments with your Professor.

Next, acquire a copy of the "If Scientists Think. . ." table from an Appendix in your Course Manual. This table has a series of statements that begin with "If scientists think the Earth is 4.5 billion years old, then 'They must have. . . .?'"  Your group's objective is to discuss and record plausible endings to each of the provided statements.  It would be a good idea to use scratch paper to record the products of your brainstorming session. You will be given 20-30 minutes to complete this table. 

Your Professor will provide you with instructions on how to share the information on your completed copy of "If Scientists Think. . .".  You may be asked to use whiteboards, a computer with projector, or other method to communicate your findings with the rest of your class members.  Pay close attention to the results from each group as they present each of their conclusions.  The overall goal of the class discussion is to reach an agreement about what to "officially" record in "If Scientists Think. . .". 

Each person will need to record the class's consensus for each question in their personal copy of "If Scientists Think. . .".