Name: ______Period: ______Date: ______

Geologic Time Scale – Metaphor Project

Background:

One of the most important ideas when studying Earth’s history is the concept of geologic time. Scientists estimate ages of events in Earth’s history not in tens or hundreds of years, but in millions and billions of years. By studying the fossil record and using various absolute dating techniques, scientists have divided the time into smaller, more manageable chunks defined by key events and/or fossils linked to that time period.

So what is a metaphor? A metaphor is a figure of speech used to show a comparison between two things that are unrelated yet may share some characteristics. Suppose we said the world is a stage. Is the world literally a stage? Or are there similar characteristics between the world and a stage?

Procedure:

1.  Your project is to choose a metaphor for geologic time. Be creative! The list of possible metaphors is limited only by your imagination. Consider comparisons that can be made between things like time and distance, time and volume, time and time, and so on. Whatever you choose, it must be an exact measurement in order for the comparison to work.

2.  You will submit a written description of your metaphor. In this description you need to explain your metaphor and why you chose it. Your description should be at least one page typed and double-spaced using Times New Roman, 12-pt font.

3.  Your metaphor should be created true-to-scale, which means you will have to do some math! Using your notes and the list of major events in Earth’s history, you will need to determine where the different eras and periods begin based on your metaphor as well as where events on the list below would fit into your metaphor. You may use an formula you like to do your calculations, but you must show all of your work on a separate sheet of paper.

a.  The best way to calculate the relationship between Earth’s history and your metaphor is to use simple ratios.

b.  The general equation you will use to find the necessary numbers for your true-to-scale metaphor is:

Known age of past event (years before present) = time scale metaphor equivalent (unknown)

Known age of the earth (years before present) = metaphor maximum measurement

4.  You will then create a visual representation of this metaphor. This visual representation is unique to the metaphor you have chosen so no two models will likely be the same and, like choosing your metaphor, your visual representation is limited only by your imagination. Your model should be easy to read and all time periods and events should be clearly labeled. Your model should be colorful and include pictures if possible. This is where most of your creativity score will come from.

Some Important Dates in the History of the Earth
Millions of Years Ago (mya) / Event
2.6 / Quarternary Period begins
3 / Early hominids (Australopithecus)
60 / First Primates
66 / Cenozoic Era begins
Tertiary Period begins
66 / Mass extinction of the dinosaurs (K-T event)
145 / Cretaceous Period begins
200 / Pangaea begins to break apart
201 / Jurassic Period begins
230 / First dinosaurs appear
252 / Mesozoic Era begins
Triassic Period begins
252 / Largest mass extinction event in Earth’s history
299 / Permian Period begins
300 / Pangaea forms
320 / Appalachian Mountains begin forming
359 / Carboniferous Period begins
419 / Devonian Period begins
443 / Silurian Period begins
486 / Ordovician Period begin
530 / Cambrian explosion (many invertebrate marine organisms evolved at one time)
541 / Paleozoic Era begins
Cambrian Period begins
1,000 / First multicellular organisms
1,800 / First eukaryotes (cells with a nucleus)
2,400 / Oxygen begins to accumulate in atmosphere
3,500 / First prokaryotes/bacteria (cells without a nucleus)
4,600 / Origin of the Earth
Grading Rubric
1 / 2 / 3 / 4 / Score
Chosen Metaphor / Metaphor is unrealistic and will not work as described / Metaphor is somewhat realistic; adaptation to geologic time is difficult / Metaphor is realistic and is easily adapted to fit geologic time / Metaphor is realistic, creative and original; works well within the scope of geologic time
Metaphor Explanation / Explanation is not clear and does not meet the expectation outlined above or is not included. / Explanation is difficult to understand with many spelling and grammar errors; has not been typed / Explanation is clearly stated but has several grammar and spelling errors; some of the criteria are missing / Explanation is clearly stated and largely free of grammar and spelling errors; work meets all listed criteria
Math Calculations / Calculations are missing or are completely incorrect / Some calculations are correct, but no work has been shown / Most calculations are correct based on the metaphor, only some of the work has been shown / All calculations are correct based on the chosen metaphor and all work has been shown
Visual Model / Model is sloppy and missing most of the required information or has not been completed / Model is difficult to read; several time periods and/or events are missing; unorganized; no pictures have been included / Model is somewhat neat and easy to read; well-organized; some time periods or events are missing; very few pictures are included / Model is very neat and easy to read; all time periods and events have been included; well-organized and accurate; when appropriate, pictures have been included
Overall Creativity / Overall project lacks any creativity or originality; work does not meet basic expectations; little thought has been put into final implementation / Overall project shows some creativity but no originality; work barely meets basic expectations. / Overall project shows originality and creativity; work meets basic expectations / Overall project shows originality, insight and a great deal of creativity; work goes beyond basic expectations and shows a deeper understanding
Final Grade