11-12
Grade:
Subject:
Earth Science /
Marine Science
Topic:
Geologic Time
The Geologic Time Scale
Adam Fox
January 2010
Coastal Carolina University
NSF GK-12 Program
http://kingfish.coastal.edu/GK-12
Standards Addressed:

SC Standard ES-6: Students will demonstrate an understanding of the dynamic relationship
between Earth’s conditions over geologic time and the diversity of its organisms.
Summary:

The purpose of this activity is to help put Earth’s history and geologic time in perspective. We
will use a football field to represent all of Earth’s history, with each yard representing 50 million
years.
Performance Objectives:



Students will demonstrate a basic understanding of the scale of Earth’s history
Students will be familiar with scientific notation
Students will be able to perform a basic mathematical conversion when provided with a scale
Materials


1 Football field or 100-yard long space
Geologic event cards (attached)
Hook:

How big is a million?
Concept Exploration:
1. Have students answer Questions 1-3. They may not yet understand the geologic timescale, so these
are just to see what their initial ideas are.
2. It’s very hard for humans to comprehend large numbers or long timespans.
a. A “long time” for a human is a human lifespan - ~100 years or so.
3. Instead of trying to wrap our heads around large numbers, we will scale down earth’s history so it is
easier to visualize.
a. If Earth’s history was squeezed down to fit on a football field, with the present at one
goal line, each yard would represent 50 million years.
4. Demonstrate how to convert years into yards using the conversion factor 1 yd = 50 million yrs.
a. The example on the worksheet uses the start of the Paleozoic Era, 750mya.
5. Randomly assign each student an event from the second page of the worksheet. Hand out a card
(pages below). Students will complete Questions 4-5.
6. Go down list of events, having each student call out the number of yards for their event, and have the
class fill in the table.
7. Head out to the football field, and have the students place their card at the appropriate place on
the field. As a class, walk through Earth’s history from formation to the present day, briefly
discussing each event you pass.
8. Have students look back at Questions 1-3, and place a star at a more appropriate place on the
timeline for each event.
9. Students should complete Question 6.
Additional Resources:

Adapted From the Texas Natural Science Center
http://www.utexas.edu/tmm/education/lessonplans/time/index.html

Some events from History of the Universe.com
http://www.historyoftheuniverse.com/tl1.html

Another timeline resource- The Worsley School’s Timelines:
http://www.worsleyschool.net/science/files/toiletpaper/history.html
http://www.worsleyschool.net/science/files/time/line.html
http://kingfish.coastal.edu/GK-12
http://www.nsfgk12.org
Name__________________________________________________ Date____________________
Geologic Time
One year of school seems to take a long time. If you lived to be 100 years old, it might as well be
forever. It’s hard to even imagine how long that really is. But what about the pyramids? They were
built about 5000 years ago—now that’s almost impossible to imagine! But how does that compare to
how old dinosaurs are or to when the Earth was formed?
Earth is approximately 4.6 billion years old. That’s 4,600,000,000 years. We’re going to translate this
into something that’s a little easier to get a grip on. A standard football field is 100 yards long. If you
were to squeeze the Earth’s history down to the size of a football field, each yard would represent
approximately 50 million years. Today, we will examine the history of the Earth by putting it in
perspective on a more manageable scale.
Questions: Circle your answers on the timeline provided.
Take your best guess, answers for 1-3 will not be graded.
1. On a timeline of the Earth’s history, where do you think the age of dinosaurs would first appear?
< Earth Formed
Present Day >
2. On a timeline of the Earth’s history, where do you think humans would first appear?
< Earth Formed
Present Day >
3. On a timeline of Earth’s history, how old do you think the continents are?
< Earth Formed
Present Day >
Remember:
109 = 1,000,000,000 one billion
106 = 1,000,000 one million
105 = 100,000 one hundred thousand
104 = 10,000
ten thousand
Example: How do we translate history onto the football field?
750 million years ago marked the start of the Paleozoic Era of Earth’s history. Where would this fall on
our football field scale?
Scientific notation: 750,000,000 = ___________________. 50,000,000 = ______________________.
(7.5 x 108 years) x
(
____1 yard____
5.0 x 107 years
)
=
=
__7.50 x 108__
5.0 x 107
__7.5__
x (108 – 107)
5
= 1.5 x 101
= 15 yards
Therefore, if the goal line represents the present, you would have to walk to the 15-yard line to reach the
beginning of the Paleozoic Era, 750 million years ago.
Event
A Formation of the Earth
Approximate Age
4.6 billion years
B Oldest known rock
4.3 billion years
C First single-celled organism
4 billion years
D Age of most continental crust
3.7 billion years
E First viruses appear
Blue-green algae
F
(First oxygen-producers)
G First fungi appear
3.5 billion years
H First multi-celled organism
Precambrian Extinction
I
(70% of all life wiped out)
J First shellfish appear
700 million years
K First fish appear
510 million years
L First true plants appear
498 million years
M First sharks appear
390 million years
N First amphibian appear
375 million years
O First reptile appears
Permian-Triassic Extinction
P
(99% of all life wiped out)
Mesozoic Era begins
Q
(Age of the dinosaurs)
R First mammal appears
325 million years
S Age of most oceanic crust
180 million years
T First known bird appears
160 million years
U Rocky Mountains formed
80 million years
V Extinction of the dinosaurs
65 million years
W First proto-humans appear
3.5 million years
X Earliest modern humans appear
2 million years
Y Last Ice Age
20,000 years ago
Z Recorded human history begins
10,000 years
Distance on Field (Yards)
3 billion years
1 billion years
650 million years
570 million years
250 million years
245 million years
200 million years
4. Which event did you pick?_______
5. Convert the age of your event into yards on the football field. SHOW YOUR WORK.
6.
The Universe was formed approximately 13.7 billion years ago. Using the same scale, How
many football fields away would this be? (hint: 100 yards=1 football field) SHOW YOUR WORK.
Formation of the Earth
A.
4.6 Billion Years Ago
Oldest Known Rock
B.
4.3 Billion Years Ago
First Single-Celled
C. Organism
4 Billion Years Ago
Age of Most Continental
D. Crust
3.7 Billion Years
First Viruses Appear
E.
3.5 Billion Years Ago
Blue-Green Algae
F.
(First oxygen-producers)
3 Billion Years Ago
First Fungi Appear
G.
1 Billion Years Ago
First Multi-Celled
H. Organisms
700 Million Years Ago
Precambrian Extinction
I.
(70% of all life wiped out)
650 Million Years Ago
J.
First Shellfish Appear
570 Million Years Ago
First Fish Appear
K.
510 Million Years Ago
First True Plants Appear
L.
498 Million Years Ago
First Sharks Appear
M.
390 Million Years Ago
First Amphibian Appears
N.
375 Million Years Ago
First Reptile Appears
O.
325 Million Years Ago
Permian-Triassic
P. Extinction (99% of all life wiped out)
250 Million Years Ago
Mesozoic Era Begins
Q.
(The Age of the Dinsaurs)
245 Million Years Ago
First Mammal Appears
R.
200 Million Years Ago
Age of Most Oceanic Crust
S.
180 Million Years
First Known Bird Appears
T.
160 Million Years Ago
Rocky Mountains Formed
U.
80 Million Years Ago
Extinction of the Dinosaurs
V.
65 Million Years Ago
First Proto-Humans
W. Appear
3.5 Million Years Ago
Earliest Modern Humans
X. Appear
2 Million Years Ago
Last Ice Age
Y.
20 Thousand Years Ago
Recorded Human History
Z. Beings
10 Thousand Years Ago