By looking at layers of rocks, scientists can tell which layers are older or newer than others; however, they can not tell exactly how old these layers are.
Because this assignment is linked with your work in Assignment 3, you will have "If Scientists Think. Before scientists had modern technology to assist them in their research, they had to use their power of observation to infer the relative ages of the rocks they were studying.
The process of Relative Dating was established by Nicholaus Steno in the 1600's.
To obtain further practice with the concepts of Steno's laws and geologic dating, work through the Understanding Geological Time section of this assignment.
This portion of the assignment is an interactive web site that allows you to apply what you have learned and to learn more about how scientists tell time with geology.
Following this introduction, there are several links to different sites concerning the methods scientists use to assist them in estimating the age of the Earth.