Take a quick look at Earth's geologic time scale.

A discussion of geologic time, along with a presentation of evidence for the time span involved.

A discussion of geologic time, how scientists use the concept, and how they have determined its span.

A lengthy scholarly article that discusses the geologic time scale, its history of development, age-dating events that occurred in different eras, and how absolute and relative dating are used to assess the ages of the Earth and Moon....

This is a good source for getting an in-depth description of using radioactive decay to measure the ages of rocks. In addition to describing the process of radiometric dating, this resource also includes a geologic time scale and four...

The geology of Alberta is profiled on this site. Drop menus reveal sub-topics ..geological time scale, rock formations in Alberta, and so forth.Graphics and maps are included.

This in-depth article illustrates the concept of geologic time, and helps the learner understand why fossils are rare.

Describes plants and animals that lived during the Ordovician Period, where it falls in the geologic time scale, tectonic activity happening then, the climate and environment, and extinction events.

How do scientists know how old the Earth is? What is radioactive dating? Are there other dating methods? Get the answers to these questions and others at this site presented by the Australian Museum Online.

To describe the diversity of unicellular organisms which arose over 2 billion years of evolution.

During your lifetime, you will use more than a million pounds of rocks, minerals, and metals. Dig through this web site and find out how.