(EER's homepage, Astronomer's Education Notebook)
(EER's
homepage, Astronomer's Education Notebook)
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
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.