Lesson 2 Building a Time Line – We explored how geologists use correlation, evidence of Earth’s major events, and the fossil record to build a timeline of Earth’s history. They will create a scale model of the geologic timescale, and construct scientific explanations to enhance their understanding of how the geologic time scale is interpreted from rock strata and used to organize Earth’s history. We reviewed the fact that determining the absolute age of a rock is more accurate than the method of relative-age dating. We learned that all mass extinction events were caused by meteorites, asteroids, or comets impacting Earth. They occurred in small amounts of time, such as a few days or weeks.