Name: _______________________ # ______
Date: ____________________ Core: ______
A Walk Through Time Lab
Sometimes geologists want to know about an event that occurred before humans were around to record it. They
have evidence of when the event occurred by looking at rocks, which contain fossils and other information. To
keep all of the events in order, geologists have created the geologic time scale. The geologic time scale is
divided into 3 eons, and each eon is subdivided into eras. Eras are then subdivided into periods, which are
then further separated into epochs. This may sound confusing, but the Earth has been around for a long time
and a lot has happened! The Earth formed about 4.6 billion years ago (4,600,000,000) years ago, so to put
geologic time into terms that are easier to comprehend, we’re going to imagine that the entire history of Earth
fits onto a football field.
Materials
Geologic Time Scale
Geologic Time Football Field
Colored pencils
Calculator
Procedure
Step 1 Choose 4 different colored pencils to represent each of the geologic times. Lightly color the box in
Table 1 below for the geologic time that each color will represent on your football field.
Step 2 Complete Table 1 below to determine the beginning and ending dates of the Precambrian Time and each
of the eras that followed. Each yard on the football field represents 46 million years in geologic
time.
Table 1
Geologic Time Period
Precambrian Time
Paleozoic Era
Mesozoic Era
Cenozoic Era
Began
Distance (yds)
4.6 billion years
ago
570 million years
ago
245 million years
ago
66.4 million years
ago
Ended
Distance (yds)
570 million years
ago
245 million years
ago
66.4 million years
ago
present
Step 3 Beginning at the end zone labeled “Today” on your football field, count the number of yards away from
the end zone that would represent the beginning of the Precambrian time and mark it. Each of the lines
on the football field is 1 yard.
Step 4 Beginning at the end zone labeled “Today” on your football field, count the number of yards away from
the end zone that would represent the end of the Precambrian time and mark it.
Step 5 Lightly color all of your football field that represents the Precambrian time period with the colored
pencil you chose to represent it.
Step 6 Repeat steps 3-5 for each of the eras on the chart as well.
Name: _______________________ # ______
Date: ____________________ Core: ______
Step 7 Complete Table 2 below to determine when each of the geologic events in Earth’s history occurred.
Each yard on the football field represents 46 million years in geologic time.
Table 2
Geological Event
Approximate Age
Appalachian Mountains form
1.1 billion years ago
Earth forms
4.6 billion years ago
Himalayas form
50 million years ago
Pangaea forms
300 million years ago
Pangaea splits apart
200 million years ago
Peak of the last ice age
20,000 years ago
Oldest known rock
4.2 billion years
Distance (yds)
Step 8 Beginning at the end zone labeled “Today” on your football field, count the number of yards away from
the end zone that would represent when the Appalachian Mountains formed, mark it, and label it.
Step 9 Repeat step 8 for each of the other geologic events in Earth’s history.
Step 10 Complete Table 3 below to determine when each of the biological events in Earth’s history occurred.
Each yard on the football field represents 46 million years in geologic time.
Table 3
Biological Event
Columbus discovers America
Approximate Age
522 years ago
Earliest humans appear
2 million years ago
Extinction of the dinosaurs
65 million years ago
First amphibians appear
375 million years ago
First birds appear
160 million years ago
First dinosaurs appear
230 million years ago
First fish appear
510 million years ago
First mammals appear
200 million years ago
First multi-cellular organisms appear
700 million years ago
First plants appear
498 million years ago
First reptiles appear
325 million years ago
First single-celled organisms appear
1.2 billion years ago
Modern humans appear
Distance (yds)
200,000 years ago
Step 11 Beginning at the end zone labeled “Today” on your football field, count the number of yards away
from the end zone that would represent when Columbus discovered America, mark it, and label it.
Step 12 Repeat step 11 for each of the other biological events in Earth’s history.
Name: _______________________ # ______
Date: ____________________ Core: ______
Summary
1. Where would your birth date be on the football field? Why is it almost impossible to show a human’s life on
this scale? Would it be easier if we changed the number of years that 1 yard represents?
2. Complete the chart below using your football field AND geologic time scale.
Organism
Era
Period
amphibians
birds
fish
modern
humans
plants
reptiles
3. How many years are represented by 10 yards? What events are within the first 10 yards of the football field
from the “Today” end zone?
4. Look at your geologic time scale. Why do you think the Phanerozoic Eon has many more divisions and
dates associated with in than the Archean Eon?
Name: _______________________ # ______
Date: ____________________ Core: ______
Name: _______________________ # ______
Date: ____________________ Core: ______