This webpage of the National Park Service (NPS) and United States Geological Survey (USGS) discusses geologic time and what it represents. Beginning about 4.6 billion years ago and ending in the present day, this site exhibits (to scale) the various eras, periods, eons, and epochs of Earth's history with a downloadable geologic time scale available. Links provide maps of what the Earth looked like ... Full description.

In this activity, students are introduced to sequencing and geologic time through relative dating techniques. Students begin by categorizing cards of nonsense words, then move on to cards with pictures of fossils. Once students begin to grasp "relative" dating, they can extend their knowledge of geologic time by exploring radiometric dating and developing a timeline of Earth's history. There is a ... Full description.

In this activity, students gain an understanding of relative and numerical time by placing events in sequence and assigning relative times to the events. This will familarize them with the methods used by scientists to develop the geologic time scale. This activity contains objectives, materials, procedure, and extensions. Full description.

This Geological Society of America (GSA) site contains a detailed geologic time scale as an educational resource. It may be downloaded to a larger size, and includes all Eras, Eons, Periods, Epochs and ages as well as magnetic polarity information. Full description.

This lesson shows students that age-dating rocks involves counting atoms and comparing the counts. Students use simulated rock samples, which show a highly magnified selection of 128 atoms, each sample with a different proportion of the atoms of two different elements: a parent radioisotope, and its daughter product. By counting the parent radioactive atoms and knowing the half-life of those atoms, ... Full description.

This lesson will inform students about the high level of confidence we have in the geological ages of an old Earth. At the same time, it should reveal an example of pseudoscience, which should be part of any effort to improve science literacy and critical thinking. Students are taken through a combination of background information and interactive experiences, and checked frequently by questions to ... Full description.

This lesson discusses the clear evidence of geological events over many millions of years. Students count the number of varves (annual layers of sediment) in shale billets, taken from the Green River Formation in Wyoming. The count is then extended to reflect the entire 260 meters of sediments where the billets originated, a period of approximately 2 million years. This provides a tangible experience ... Full description.

These procedures for creating a timeline from the Big Bang to the present include directions and images suitable for all major events in time, downloadable so they can be copied and made available to students to build. Scale is 1 mm = 1 million years. Users have the option of starting at the Big Bang or the beginning of our solar system. Full description.

In this lesson students will experience how geological and biological events have occurred in a clear sequence of vast but measured time. Students are taken on a simulated voyage backward in time, to the beginning of our planet. They witness that beginning, the origin of life, and a number of key events leading to the present. This becomes a dramatic experience, involving body and mind, helping students ... Full description.

In this lesson, students will learn that geological time can be measured in several different ways, providing independent lines of evidence for measuring deep time and sequencing geological and biological events of the past. Students explore different methods of measuring geological time, comparing the time dimensions, mechanisms, and materials used for each. Full description.