Introduction

How old is the universe? How old is our sun? How old is the earth? When did life first appear on the earth? How long have Homo sapiens inhabited the earth? The answers to most of these questions differ by billions of years. However, to many middle school students, these answers boil down to variation on a single theme: really old, a long time ago, and for a long time. Ask your colleague teaching history: She or he can tell you students have difficulty conceptualizing and contrasting the different historical eras, such as the medieval period in Europe and the colonial period in America. Thus, it is no surprise that geologic time is difficult for students of all ages to conceptualize.

The Earth and Space Science content standards, grades 5-8, of the National Science Education Standards include: Structure of the earth system; Earth's history; and Earth in the solar system; none of which can be mastered without good conceptual understanding of geologic time. In order to gain that understanding, students need numerical literacy, including both comprehension of scientific notation and an accurate concept of the difference between a million and a billion. Additionally, knowledge of the nature of science in general, and geologic science in particular, is needed.

Not a geology major or mathematician? No worries! This publication contains resources designed to do three things. The first is to complement teacher content knowledge and its relationship to the nature of geologic science. Geology is not a laboratory-based science lending itself to traditional notions of controlled experiments; rather it is a historical science requiring different methods. Second, we supply teachers with hands-on/minds-on lessons to develop student understanding, and third, we provide career-oriented resources to expose students to scientists whose work involves concepts in geologic time.

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by Mary LeFever

Mary LeFever is a resource specialist for the Middle School Portal, and a doctoral candidate in science education at Ohio State University. She has taught middle school and high school science and is an adjunct instructor of biology and natural sciences at Columbus State Community College. Please email any comments to msp@msteacher.org.

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Copyright September 2007 — The Ohio State University. This material is based upon work supported by the National Science Foundation under Grant No. 0424671. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

This work is licensed under a Creative Commons License.