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Toilet Paper Geologic Time Scale


LEVEL
Ages: general audiences

RATIONALE
A graphic demonstration of the enormous extent of geologic time compared to recent time.

LENGTH
An hour, in advance, to prepare the roll.
10-15 minutes for demonstration, plus 10 minutes or so to re-roll.

MATERIALS

PREPARATION

  1. On a flat, protected surface, unroll the first sheet or so of the roll. Test the marker(s) for clarity and bleedthrough. Change markers or gear your writing based on the test. If you wish to draw long, dashed lines to show the eons, eras, and periods, try one on your test sheet. Discard the test sheet(s).
  2. Using the perforations between sheets as a ruler (the first is zero), mark the dates and names of items as listed in the table below.
  3. Re-roll the toilet paper. If it tears, repair with tape.

PROCEDURE

Starting at one end of a long hallway, unroll the toilet paper until you reach the end. Note the varying distances.

Re-roll the model to use again (repair with tape if necessary).

 

SPACING

sheets

Event

Geological time (Number of years before present)

Comments

0.00

Present

0

 

0.0005

Modern man

10,000

 

0.01

Neanderthal man

100,000

 

0.03

First use of fire

500,000

 

0.06

Worldwide glaciation

1,100,000

 

0.07

Homo erectus

1,300,000

 

0.08

Linking of North and South America

1,500,000

 

0.08

Oldest stone tools

1,600,000

 

1.15

Beginning of Quaternary period (end Tertiary/Neogene)

23,000,000

 

0.15

Australopithecus

3,000,000

 

0.50

Beginning of Antarctic ice caps

10,000,000

 

0.50

Opening of Red Sea

10,000,000

 

0.75

Formation of Himalayan Mountains

15,000,000

 

1.15

Beginning of Tertiary/Neogene period (end Paleogene)

23,000,000

 

 

1.25

First evidence of ice at the poles

25,000,000

 

2.00

Collision of India with Asia

40,000,000

 

2.50

Early horses

50,000,000

 

2.50

Separation of Australia and Antarctica

50,000,000

 

3.00

Early primates

60,000,000

 

3.00

Opening of Norwegian Sea and Baffin Bay

60,000,000

 

3.00

Alps form

60,000,000

 

3.25

Beginning of Tertiary/Paleogene period

65,000,000

 

3.25

Beginning of Cenozoic Era

65,000,000

"recent life"

3.25

Cretaceous Period, Mesozoic Era end

65,000,000

 

3.25

Dinosaurs became extinct

65,000,000

 

4.00

Rocky Mountains form

80,000,000

 

7.00

Cretaceous Period begins (Jurassic ends)

140,000,000

 

7.50

Early flowering plants

150,000,000

 

9.00

Early birds and mammals

180,000,000

 

10.40

Jurassic Period begins (end Triassic)

208,000,000

 

11.00

Opening of Atlantic Ocean

220,000,000

 

12.25

Triassic Period begins

245,000,000

 

12.25

Beginning of Mesozoic Era (end Paleozoic)

245,000,000

"middle life"

14.00

Final assembly of Pangaea

280,000,000

 

14.50

Beginning of Permian period (end Carboniferous/Pennsylvanian)

290,000,000

 

16.25

First reptiles

325,000,000

 

16.15

Beginning of Carboniferous/Pennsylvanian period (end Mississippian)

323,000,000

 

18.15

Early trees, formation of coal deposits

363,000,000

 

18.15

Beginning of Carboniferous/Mississippian period (end Devonian)

363,000,000

 

20.45

Beginning of Devonian period (end Silurian)

409,000,000

 

21.50

Early land plants

430,000,000

 

21.95

Beginning of Silurian period (end Ordovician)

439,000,000

 

24.50

Early fish

490,000,000

 

25.50

Beginning of Ordovician period (end Cambrian)

510,000,000

 

28.50

Early shelled organisms

570,000,000

 

 

28.50

Beginning of Cambrian period (end of Precambrian time)

570,000,000

rise of multicellular animals

28.50

Beginning of Paleozoic Era

570,000,000

"ancient life"

28.50

Beginning of Phanerozoic Eon (end Proterozoic)

570,000,000

"visible life" (or 544 million years ago)

35

Early multicelled organisms

700,000,000

 

40

Breakup of early supercontinent

800,000,000

 

70

Formation of early supercontinent

1,400,000,000

 

60

First known animals

1,200,000,000

 

125

Beginning of Proterozoic Eon (end Archeon)

2,500,000,000

"earlier life"

135

Buildup of free oxygen in atmosphere

2,700,000,000

 

170

Early bacteria & algae

3,400,000,000

 

190

Oldest known Earth rocks

3,800,000,000

 

200

Beginning of Archeon Eon

4,000,000,000

 

230

Precambrian time begins

4,600,000,000

 

230

Origin of earth

4,600,000,000

 

Note: I've set the scale to use 230 sheets rather than the usual 250 because it makes the conversion more obvious -- 20 million years per sheet.

Credits:

The time scale is a combination of actual numbers (for the eons and such) and approximate dates from a time scale (for events, such as "early horses"), both from:

Press, F., and Siever, R. Understanding Earth. W. H. Freeman and Company, New York, 1998. ISBN 0-7167-2836-2.

Please note that various sources will give different specific dates, but the overall scale is the important part of this activity. Many events cannot be pinpointed (the geologic record is not perfect or complete), and in any case, most of the "dividing lines" are probably gradual changes, occurring over many thousands or even millions of years.


Copyright 1997, Elizabeth E. Roettger. Permission to reproduce the instructions is granted only when full copies, including this paragraph, are reproduced and distributed.
Last updated: 12 Nov 1998. URL: http://www.nthelp.com/eer/HOATPtime.htm