1. LEQ:: What is Geologic Time
LEQ:: What is Geologic Time? How can a model help me visualize the length and vastness of geologic time? What is the Geologic Time Scale? What are the units of the Geologic Time Scale?
Key terms: geologic time, geologic time scale, eon, era, period, epoch.

2. Appreciating Geologic Time
Getting a personal vision of geologic time is a concept that is critical in Earth Science.
An easy way to get a vision of geologic time is when you begin to get a good concept of the vastness of geologic time.
A model is very helpful.

3. Lets Start with Numbers (and the power of 10)
On your notes page, print the following number:
One Thousand
1,000
One Hundred Thousand
100,000
One Million
1,000,000
One Hundred Million
100,000,000
One Billion
1,000,000,000

4. Asterisks on the page Number of asterisks on the page: 2000
Number of pages needed for 1 million asterisks
500
Number of asterisks in a ream of paper:
1,000,000
Number of asterisks in a case of paper:
10,000,000

5. Modeling Lets use the asterisks to help us make a model.
Each asterisk is 1 year.
Number of years on one page:
2000 years
Number of pages needed for 1 million years
500 pages
Number of years in a ream of paper:
1,000,000 years
Number of years in a case of paper:
10,000,000 years.

6. Units of time
Work with a partner, and list the following units of time from the largest to the smallest:
Hour Day
Millennium Century
Year Week
Month Second
Minute Decade

7. Earth’s Age Earth’s age is estimated to be: 4.6 billion years old.
4,600,000,000
Number of cases for 4,600,000,000:
460 cases
With each case having 5000 pages and each page having 2000 years.

8. Geologic Time
Earth’s history has been 4.6 billion years in the making.
This history is known as geologic time.

9. The Geologic Time Scale
Because the span of Earth’s past is so great, geologists use the geologic time scale to show Earth’s history.
The geologic time scale is a record of
Life forms in Earth’s History.
Geologic events in Earth’s History.

10. Units of Geologic Time
In a similar way we divide time into units, geologists divide Geologic time into units.
Units of geologic time (largest to the smallest):
Eon
Era
Period
Epoch
Each eon, era, period, and epoch is given a specific name.

11. What time is it? (in Geologic Time)
We currently live in the:
Holocene Epoch of the:
Quaternary Period of the:
Cenozoic Era of the:
Phanerozoic Eon