Geologic Time explains how scientists organize Earth’s 4.6-billion-year history using the geologic time scale. The video defines key Earth science and geology terms—eon, era, period, epoch, and age—and connects them to major events in the rock record, fossils, geological change, and the evolution of life. It highlights the Precambrian, Paleozoic, Mesozoic, and Cenozoic, including the Triassic, Jurassic, and Cretaceous periods. The lesson also introduces radiometric dating and radioactivity as tools geologists use to estimate the age of rocks and fossils. With clear review questions and scientific vocabulary, this resource supports curriculum-aligned learning in Earth science, geology, paleontology, and scientific methods.