It is estimated to require four hours of class time, including approximately one hour total of occasional instruction and explanation from the teacher and two hours of group (team) and individual activities by the students, plus one hour of discussion among students within the working groups.
Explore this link for additional information on the topics covered in this lesson: This activity will help students to have a better understanding of the basic principles used to determine the age of rocks and fossils. Objectives of this activity are: 1) To have students determine relative age of a geologically complex area.
Early geologists, in the 1700s and 1800s, noticed how fossils seemed to occur in sequences: certain assemblages of fossils were always found below other assemblages. Since 1859, paleontologists, or fossil experts, have searched the world for fossils.
In the past 150 years they have not found any fossils that Darwin would not have expected.
Classifying ancient organisms is also difficult, as many do not fit well into the Linnaean taxonomy that is commonly used for classifying living organisms, and paleontologists more often use cladistics to draw up evolutionary "family trees".
The geologist finds zircon crystals that were formed in igneous rock as it cooled.
The zircon traps the uranium but not lead as it cools.
It wasn't until well into the 20th century that enough information had accumulated about the rate of radioactive decay that the age of rocks and fossils in number of years could be determined through radiometric age dating.
This activity on determining age of rocks and fossils is intended for 8th or 9th grade students.