Warm-up 10/27 What is the half-life of Carbon? 2. The element chaparralium has a half-life of 24,000 years. If a fossil contains 25% of the original amount of chaparralium, how old is this fossil? Show your work!

Warm-up 10/28-29 1. Which layer of the Earth do you think is most important and why? 2. If a fossil has .195% of the original amount of an element, how many half lives have passed? 3. Which type of dating would you use to find the age of an ancient basket made of natural fibers? Why? End

Continental Drift Identify and label the different continents on your map. North America South America Africa Europe Asia/India Australia Antarctica

End Continental Drift Take 2 minutes to observe the world map. Make 2 observations about the continents’ coast lines. Make 1 inference based on your observation End

Continental Drift Take 3 minutes and work with your partner to try and fit the continent puzzle pieces together. End

End Continental Drift Do they fit together perfectly? What may have caused the coastlines to change over time? Come up with 2 possible reasons (2 minutes) End

Continental Drift Look at the small pictures on your puzzle pieces. Those are fossils found in those areas of each continent. Take 2 minutes to observe the fossil placement. Make 2 observations Make 1 inference End

Continental Drift Rearrange your puzzle so that all of the fossil segments line up. (2 minutes) End

End End Continental Drift Take 3 minutes to draw in dots along the plate boundaries to show recent earthquakes. (large dots = more activity, small dots = less activity) End End

Continental Drift Take 2 minutes to draw in triangles to show volcanic activity. End

Continental Drift Take 2 minutes to observe the marks you just made on your map. Make 2 observations Make 1 inference End

Concept with no mechanism Continental Drift Alfred Wegner Concept with no mechanism

Wegener’s evidence of drift The continents fit together. Fossils of the same organisms are found along the coasts of different continents.

Pangaea Supercontinent 300 million years ago Cycle

Plate Tectonics Scientific theory (concept + mechanism) Lithosphere is broken up into “tectonic plates” Moved by convection of asthenosphere Past plates and current plates How do we know? How many? Farallon Plate Farallon Plate video in picture

More Evidence for Plate tectonics Seismic, volcanic, and geothermal activity along plate boundaries.

How would you explain this evidence?

Evidence for Plate tectonics 4. Sea Floor Spreading Mid-ocean ridges Tectonic plates moving separating New magma rises Form new oceanic crust Older crust pushed away

More Evidence for Plate tectonics 5. Magnetic Reversals Molten rock Magnetic minerals Align with magnetic field Magnetic field reverses 177 times in 85 million years Last 600,000 years ago Recorded in rock Similar pattern to age of rocks Reverses every 500,000 years or so (exact division is 480,225.98)

Causes for Plate Tectonics Convection Cools Asthenosphere More dense Heated rock Expands and rises

2 main types of movement 1. Spreading 2. Subduction New material pushed up at ridges Pushes older material away 2. Subduction Denser plate sinks Pulls rest of plate Picture has hyperlink to http://www.youtube.com/watch?v=KCSJNBMOjJs National Geographic – Colliding Continents

Warm-up 11/3 & 7 Which piece of evidence for continental drift do you think is most compelling and why? Compelling: strong and forceful, having influence