1. The Theory of Plate Tectonics
Activity 42

2. Activity 42: The Theory of plate Tectonics
Challenge: How did continental drift lead to the theory of plate tectonics?
Key Vocabulary:
Plates
Plate Tectonics
Theory
Read the Introduction on Page D-29

3. Record the Following Definitions in your notebooks:
Plate  large sections of earth’s surface Plate Tectonics  The movement of Earth’s lithospheric plates Theory  a thoughtful, TESTABLE explanation of all relevant observations. A scientific theory is one that explains observations and can predict future observations.

4. Glue in SS 42.1
Review the Analysis questions on page D-30 and the questions on SS42.1 We will watch the video segments on continental drift and plate tectonics. Answer as many questions on SS 42.1 that you can. Answer Analysis Questions 1-3 in your notebooks.

5. Answers to SS 42.1: a. an idea All of the statements should be checked
c. The continents were once part of a single land mass called Pangea
b. volcanoes
b. The earth’s crust is made of large pieces, called plates, that have moved over time
c. Old crust is destroyed and new crust is formed at plate boundaries
a. California is located in an area where two plates are sliding past each other
true

6. Analysis Questions:
Coal is formed when warm wet climates (such as swamps) when large amounts of plants die and are buried over geological time. Today, the Arctic is a cold, snowy area. It is surprising to find the fossil remains of a material that formed in a climate so different than that of the present-day Arctic

7. The risk is low, since volcanoes are most likely to occur at plate boundaries

8. Possible Responses to Analysis Question 3
Continental Drift
Both
Plate Tectonics
Describes continents
Continents rearrange (join together and drift apart)
Original idea
Proposed by Alfred Wegener in 1915
Occur over geological time
Land was once all connected in supercontinent known as Pangea
Land masses have moved over the earth’s surface
Relies on evidence from fossils and rock layers
Describes the earth’s plates (i.e. including crust under oceans)
Lithosphere is destroyed and formed at plate boundaries
Modern theory supported by additional evidence such as satellite measurements of continental movement
Helps explain earthquakes, volcanoes, mountain formation.