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A Mini-Lesson


13 Ways to Tell Time


author unknown




Geo/Paleo Patterns



Students explore different ways gelogical time can be measured: comparing the time dimensions for each method, the mechanisms of each method, and the materials used.


Geological time can be measured in several different ways, providing independent lines of evidence for measuring deep time and sequencing geological and biolgical events of the past.


Dating-Methods graph
Text: "13 Ways to Tell Time Backwards" (2 pages)
Work sheet to help students to extract info from text


 (see end of lesson for the formatted handouts).

See materials


To be used in conjunction with a timeline activitiy or the "Time Machine", either before or after. Also can be used with a lesson on the concept of half-life and radiometric dating.

Hand out the 4 pages (graph and worksheet can be back-to-back, as can the 2 pages of the text, making 2 sheets total).

Should take no more than one 45-55 minute period, or as take-home assignment.


Strahler, Arthur N. Science and Earth History. 1987. Prometheus Books. Ch. 17 & 19.

TalkOrigins Archive; "Radiometric Dating and the Geological Time Scale".


Some of the ideas in this lesson may have been adapted from earlier, unacknowledged sources without our knowledge. If the reader believes this to be the case, please let us know, and appropriate corrections will be made. Thanks.

1. Original Source: Larry Flammer, 7/95

2. Reviewed / Edited by: Martin Nickels, Craig Nelson, Jean Beard: 12/15/97

3. Edited / Revised for website by L. Flammer 8/99


 Text (2 pages)

Dating Methods graph

Work Sheet


 The following pages are in Adobe Acrobat pdf format in order to maintain their intended layout for easy printing of handouts. Only a "thumbnail" reduced size image of the first page is showing (if more than one page is in that file). For enlarging and copying, (and seeing other pages in that file), you will need to download the free Acrobat Reader from Adobe (unless it's already installed in your system). Then just click on the blue file name above, below, or next to the first page. You may see the "Acrobat Exchange" (Reader application) loading, then the pages will display. You might need to shift-click and drag the lower left corner of the page to enlarge it, or click the magnifying glass on the menu bar.

If this doesn't seem to work, you might need to load and/or enable the PDFViewer plug-in by following one of these protocols:

For Netscape Communicator: EDIT>Preferences>Navigator>Applications (then scroll down to "Portable Document Format (PDFViewer)", click on it, then click OK; if it's not there, click on "New", and add it in).

For Netscape Navigator: OPTIONS>General Preferences>Helpers (scroll to check for PDF on list, add it if it isn't, then click OK to activate it.

For other browsers, or problems with this, check with your browser tech support, Adobe tech support, or, in dire frustration, e-mail me. If nothing else, I will mail you hard copy of the formatted pages desired.

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