1. LEQ: How do geologists and paleontologists determine the relative age of rocks? Part 1
Key Terms:
Absolute Age,
Relative Age,
Law of Superposition,

2. Absolute Age Turn to page 110.
Absolute age is defined as the number of years since an object or organism formed.
Examples:
Mr. Kraynak is 59 years old.
Mr. Pilsitz is 35 years old.

3. Relative Age
Relative age is defined as the age of an object or organism as compared to other objects or organisms.
Example:
Mr. Kraynak is older than Mr. Pilsitz.
Mr. Pilsitz is younger than Mr. Kraynak.

4. Classifying Absolute VS. Relative Age
Classify each of the following statements about children in a family as either an example of absolute or relative age.
Anthony is the youngest.
Melony is 4 years old.
Michael is older than Sarah.
Sarah is 16 years old.
Ashley is older than Melony, but younger than Sarah.

5. Children in the Family Anthony is the youngest. Melony is 4 years old.
Relative Age
Melony is 4 years old.
Absolute Age
Michael is older than Sarah.
Sarah is 16 years old.
Ashley is older than Melony, but younger than Sarah.
Place the children in order from the youngest to the oldest !

6. Children in the Family Correct Order
Anthony
Melony
Ashley
Sarah
Michael

7. Interpreting Sequence
Read the following story carefully. Then determine the correct order for the sentences. Be aware that the order has been mixed up!
1. I got out bread, peanut butter and jelly.
I ate the sandwich.
I put the two pieces of bread together.
I spread a layer of jelly on another piece of bread.
I was hungry.
I spread a layer of peanut butter on a piece bread.
How did you determine the order of the sentences?
Geologists apply the concepts we’ve learned and a few laws of geology to determine the relative age of rock layers.

8. Position of Rock Layers
Law of Superposition
In horizontal sedimentary rock layers
Oldest layer is at the bottom.
Each higher layer is younger than the layer below it.
Youngest layer is at the top.
Geologists and paleontologists use this law to determine the relative age of rock layers.

9. North Rim of the Grand Canyon
The following is a picture taken of the north rim of the Grand Canyon in Arizona.
Observe the picture, and see if you can pick out the different rock layers.

10. Journal Entry: 1. Which layer is the oldest?
Kaibab Limestone
Toroweap Limestone
Coconino Sandstone
Hermit Shale
Supai Sandstone
Redwall Limestone
Journal Entry: 1. Which layer is the oldest?
Journal Entry: 2. Which layer is the youngest?
Journal Entry: 4. In which layer would you expect to find the oldest fossils?
Journal Entry: 3. Is the Hermit Shale older or younger than the Coconino Sandstone?

11. Other “Laws” of Geology
In part II of the power point we will discover the other laws of geology geologists use as other clues to determine the relative age of rock