1. More Patterns: Ages of Rocks on Earth

2. How do we know how old rocks are? This isn’t our goal here. Most methods for dating rocks use radioactivity – the process of atoms falling apart at a predictable rate. To learn more, visit the Utah Geological Survey at http://geology.utah.gov/surveynotes/gladas ked/gladage.htm

3. Can we compare age patterns on Earth with other planets? No. To tell the age of a rock, it has to go to an Earth lab So we know ages from the Moon, and from chunks of Mars that ended up as meteorites (about 120) But we don’t know many ages, and we don’t know where the meteorites came from on Mars.

4. Let’s look for patterns Find the handout called Age Patterns on the Earth Find your maps: –Age of Rocks on the Continents –Age of the Ocean Floor

5. http://bc.outcrop.org/images/tectonics/press4e/figure-02-14.jpg What do the different colors on this map mean?

6. http://www.lithosphere.info/TC1-2006/TC1_Fig2-ages-062006.jpg What do the different colors on this map mean?

7. Time to think about the patterns Talk to your partner about the questions in the graphic organizer. Fill in the chart.

8. Share what you figured out with another partner In a minute you will find your Venus partner. You will do a Structured Think Pair Share with that partner. Make this chart in your journal: Think Pair Share

9. Structured Think Pair Share First you will write what you think about the question in the Think box. Then you and your partner will each describe your ideas. Write your partner’s ideas in the Pair box. Finally you and your partner will decide on a common answer to the question. Write that in the Share box.

10. Question: How are the age patterns on the continents different from the age patterns on the ocean floors?

11. Time to share Let’s make a class share sheet about age patterns on the Earth.

12. One more Notice & Wonder Pull out your journal Make a N&W chart: I noticed…I wonder…