The History of the Earth
Teaching Guide
SCIE 203
© JLB Anderson, 2009
Student will learn about time lines and representing large amounts of time in ways that their own
students can visualize. They will create a personal time line of their own life from birth to present. They
will then create a timeline of events in Earth’s history.
Materials:
Metric rulers
Adding machine tape – 4.5 meters per timeline
Thinking about Big Numbers:
1. What is a million? A billion? What are good ways to represent these huge numbers for your
students?
2. This activity is a good lead-in to the context of the Earth System in terms of where the Earth
came from in the first place. Talking about the history the Earth & the Universe necessarily
involves large numbers, so it’s a good idea to start with a discussion of how to think of numbers
like millions and billions.
3. Start by asking students how to represent such large numbers. We are going to use common
objects to get a sense of how many objects these numbers represent. Students can work in
groups or pairs to figure out the following:
a. How old are you when your heart has beat one million times? One billion?
b. How long would it take you to count to one million? One billion?
c. How tall is a stack of one million pennies? One billion?
d. How long is one million toothpicks laid end to end? One billion?
e. How long is a chain of one million paperclips? One billion?
f. How much time would it take you to drive one million miles? One billion?
g. How large of a volume would one million M&Ms take up? One billion?
h. And whatever else you can think of…
i. The nice thing about this activity is it gets students making assumptions and basic
calculations. Students should come up with final distances, times, and volumes that we
can relate to, for example, the volume of an Olympic swimming pool (15m x 25m x 2m
=2500 m3), volume of a dumpster (11 m3), number of seconds in a year (31,556,926
sec/year) or a day (86,400 sec/day), number of miles (1609 meters/mile), distance
around the Earth (~40,000 km = 25,000 miles). Students should work to come up with
these analogies themselves, but these ideas should help the instructor. ?? What is the
volume of the classroom??
4. Discuss the results as a class and try to come up with other ways to relate these large numbers
to elementary-aged students. Think about how you might represent the Earth’s history in a
visual way that your students could understand.
Personal Time Lines
5. Start by having students think about time. How do they keep track of time? How much time is a
long/short time? If they wanted to figure out what they were doing on June 1st 3 years ago,
where might they look? What if they wanted to find out what was happening on Earth 300
years ago? What about 300 million years ago?
6. Have each student create a list of significant events that have occurred in their personal history
along with the month/year the event occurred. It would be nice to have a dozen or more
events. Some events might include:
a. Birthday
b. First day of Kindergarten, 6th grade, 9th grade
c. Graduation from high school
d. First day of college
e. Driver’s license
7. Have students draw a diagonal line in their science notebook that is their age + 2 centimeters
long (so, if the student is 22, they draw a 24 cm long line). Draw tick marks on the line at each
centimeter spot and label them. Each centimeter represents 1 year of their life. The left side of
the line represents today and the past is to the right.
8. On this timeline, students will locate each event they identified from their life.
** It might be good to have students complete through this part as homework prior to class. **
9. As a class or in groups, discuss this activity and compare timelines. You can also talk about
dividing the time line into common Eras like grade school, middle school, college, etc.
The History of the Earth
10. The Earth formed 4.57 billion years ago. Can you use the same scale as your timeline to
represent the Earth’s history on a piece of paper? What might be a good scale to use? (We’ll
use 1 cm = 1 million years.)
11. First have students brainstorm a list of important events in Earth history.
12. In their science notebooks, have students make predictions and turn them in:
f. How many years have modern humans been on Earth?
g. How many years since our earliest hominid ancestors?
h. When did the dinosaurs die?
i. When did shelled life first appear on Earth?
j. How many years did dinosaurs live on Earth?
k. When did the earliest life forms appear on Earth?
l. When did the last ice age end?
m. How old is the oldest rock on Earth?
13. Have students select a partner at their table and look over the list of important events in Earth’s
history listed below.
14. Students need to search online to find out when these events occurred. They then number the
events in chronological order and construct a timeline on the paper roll. Have students figure
out the appropriate scale they need to use. (The tape is 5 meters long, so the scale will be 1 mm
= 1 million years). They will mark all of the events on the time line in their correct relative
position.
15. Students also need to indicate the divisions of geologic time on their timescale.
Important Events in Earth History
Historical & Archaeological
Beginning of Iron Age
1200 B.C
Development of Egyptian
Civilization
5000 BC
Evidence of ground stone tools
10,000 BC
Evidence of humans in North
America
17,000 BC
Biological
First shelled organisms
570 million years ago
Evidence for earliest single cell
algae (stromatolites)
3.8 billion years ago
First fish
510 million years ago
First land plants
475 million years ago
First flowering plants
130 million years ago
First mammals
200 million years ago
First dinosaurs
245 million years ago
Dinosaurs go extinct
65 million years ago
The “Great Extinction” (PermianTriassic)
248 million years ago
First amphibians
350 million years ago
First reptiles
248 million years ago
Homo Sapiens appears
600,000 years ago
First birds
150 million years ago
Australopithecus appears
3.2 million years ago
Earliest monkeys
35 million years ago
First insects
380 million years ago
First multi-cellular life
1.4 billion years ago
Photosynthesis
3.5 billion years ago
Geological
End of the last ice age
20,000 years ago
Formation of the Earth
4.57 billion years ago
The Iron Catastrophe (formation
of Earth’s core)
4.5 billion years ago
Oldest rocks in Minnesota
3.6 million years ago
Himalayas start to form from a
collision of India with Asia
22 million years ago – present
Oldest Zircon mineral (Earth’s
crust)
4.4 billion years ago
Formation of the Moon
4.45 billion years ago
Winona Bluff rocks are
deposited
480 million years ago
Appalachian Mountains Form
1.1 billion – 280 million years
ago
Pangea breaks up
150 million years ago
North America tries to split in
half at the Mid-Continent Rift
1.2 – 1.0 billion years ago
Rocky Mountains Form
360 - 50 million years ago
Buildup of Oxygen in the
atmosphere to today’s levels
2.4 billion years ago
Oldest known rock on Earth
4 billion years ago
Earth’s Oceans form
4.35 billion years ago