2. What do you notice about these two pictures?

3. The Earth’s surface is broken into rigid plates that move in relationship to one another.

4.  Plate tectonics is a theory that describes the formation of movements and interactions between the tectonic plates.  What is a theory?

6.  In 1912, a German scientist named Alfred Wegener proposed a hypothesis called continental drift.  What is a hypothesis?  He proposed that the continents had moved or drifted apart over time.  He studied this hypothesis his entire life, but was never successful. He could not explain how the continents had shifted over time.  He did however, pave the way for plate tectonics.

7. Theory that the continents have moved or drifted over time from one location to another. Ice Age: Continental Drift

9.  In the 1950’s and 1960’s scientists made major discoveries about earthquakes and volcanoes.  These discoveries led to the theory of plate tectonics.

10.  The theory states that the continents are embedded on plates. As these plates move, they carry the continents with them. Oceans are also a part of the plates.  This theory is supported by knowledge of important geologic processes (earthquakes and volcanoes).

11.  Data indicates that earthquakes and volcanoes do not occur randomly. Instead they are primarily located on plate boundaries.  The theory of plate tectonics helps to explain this pattern.  These plate boundaries are areas of high heat flow, where molten rock moves upward to Earth’s surface, causing volcanic activity.

13.  A mid-ocean ridge is a long chain of volcanic mountains on the ocean floor with a deep central valley.