How do scientists know what the Earth was like in the past? This second installment of a six-part series focuses on paleoclimates and provides an overview of how geologists determine information about past climates using fossil...

Students discover the various ways in which tree rings can give information. After a brief disucssion of concentric tree rings, they use cross section cut outs of tree rings to identify the time and type of various naturally occuring...

Fifth graders study environmental changes by examining the annual rings of a cross-section of a tree trunk. They access websites to complete a worksheet on the parts of a tree. They count the annual rings on a tree slice while observing...

In this absolute time worksheet, learners answer eleven questions about ways to measure the age of fossils. They define half-life, answer questions about radioactive dating, tree rings and varves.

In this absolute time worksheet, students define radiometric dating, tree rings and varves as means to measure absolute time. They are given information about each of these methods of dating.