Where in Time?

In this article, the authors describe an activity developed to assist students with constructing their own understanding of Earth's history and provide questions to help teach the geologic time scale. The lesson is aligned to the following National Science Education Standards: Science as Inquiry, Earth's History, and Nature of Science. While working through the activity, students learn science concepts related to geologic time and the value of cooperation and effective communication. The lesson begins by placing students into small groups of three or four and handing out a card to each student. Heterogeneous groups work well for this activity. One side of the card is labeled with a role (facilitator-keeps track of time, recorder-writes group answers, communicator-speaks for the group, materials manager-gathers and returns supplies). For a group of three, the tasks of facilitator and communicator are combines. A different numbered task is written on the back of each card, as follows: (1) List some big events that you have heard occurred last year; (2) List some big events that have occurred in the United States since 1776; (3) List some big events that you have heard occurred more than one million years ago; and (4) Three different types of measurements for time are calendar, historical, and geologic. How is a "big event" in geologic time different than a big event in calendar or historical time? Students are given about 12 minutes to work cooperatively in completing all four tasks. The facilitator should give each student three minutes to read their task, solicit information from the group, and record responses. A resource list is provided at the end of this article. (Contains 4 figures)