5. Seafloor Spreading - Sources and Standards

This activity combined the ideas from 1) a simple paper Seafloor spreading model by Ellen Metzger and 2) a more detailed shoebox Seafloor spreading model by John Lahr. Both lesson plans provide excellent background information and excellent alternative models.

The best resources for more information on Seafloor spreading can be found at:

  • This Dynamic Earth has an excellent section on how the theory of plate tectonics was developed using ocean floor data.
  • The Wikipedia articles on seafloor spreading and subduction provide excellent, concise summaries as well as beautiful images.
  • The animations on the front page of this lesson were created by the USGS. Other plate tectonics related animations may be found on their website.

The table of plate motion was created using the Rice University Plate Motion Calculator.

Grade 6
Plate Tectonics and Earth's Structure
1. Plate tectonics accounts for important features of Earth's surface and major geologic events. As a basis for understanding this concept:
a. Students know evidence of plate tectonics is derived from the fit of the continents; the location of earthquakes, volcanoes, and midocean ridges; and the distribution of fossils, rock types, and ancient climatic zones.
b. Students know Earth is composed of several layers: a cold, brittle lithosphere; a hot, convecting mantle; and a dense, metallic core.
c. Students know lithospheric plates the size of continents and oceans move at rates of centimeters per year in response to movements in the mantle.
d. Students know that earthquakes are sudden motions along breaks in the crust called faults and that volcanoes and fissures are locations where magma reaches the surface.
e. Students know major geologic events, such as earthquakes, volcanic eruptions, and mountain building, result from plate motions.
f. Students know how to explain major features of California geology (including mountains, faults, volcanoes) in terms of plate tectonics.