Shifting Continents: A Case Study in Scientific Revision
Even though you may not feel it, the earth is moving beneath your feet. The tectonic plates have been moving for millennia and have caused volcanic eruptions, earthquakes, tsunamis, and continents to change shape. This must take an immense amount of energy. Where does it come from? The heat from the earth’s inner core drives the movement of the plates. This heat energy is left over from the formation of the earth and some comes from the decay of naturally occurring radioactive materials. Today a lot is understood about the geologic processes. However not too long ago it was a mystery how mountains were formed and why earthquakes and volcanic eruptions happened. Many hypotheses were put forward that eventually were proven false. This is a normal part of the scientific process. Whenever new discoveries force scientists to reconsider their hypotheses, theories, and data, they do just that. Therefore, people think of science as a collection of concepts that are always being revised. The shift from the theory of continental drift proposed by Alfred Wegner in 1912 to modern plate tectonic theory is an example of this constant revision of scientific understanding as experiments generate new information.
For additional information on plate tectonics and Alfred Wegner check out this Science Center link:
Using what you learned about plate tectonics, Alfred Wegener, and the basics of scientific investigation from the previous units discuss the following:
- Navigate to the following site: U.S. Geological Survey Earthquake Map. (2016). Retrieved from http://earthquake.usgs.gov/earthquakes/map/Zoom out to see all the earthquakes that have happened worldwide today. List the most recent earthquake and its magnitude. How many earthquakes have happened in the last day? Why do so many occur near plate boundaries (red lines on map)?
- Look at the following map of the world where triangles represent active volcanoes:NOVA: Teacher’s Images. (2015). Retrieved from
Why do so many occur near plate boundaries (yellow lines on map)?
- Pick one active volcano or earthquake from around the globe or a historical geological event and explain the following
- What plates or hot spots it is associated with.
- How the plates or hot spots are causing/caused the volcanic event/earthquake.
- How energy from deep within the earth is/was transferred to and released during the volcanic event/earthquake.
- If Alfred Wegener were alive today, and had access to the technology and data that exists today, share a form of evidence that he could have added to his hypothesis or would have changed his hypothesis. Try to share a different form of evidence from those shared by your classmates and/or add to their posts by describing how the evidence is collected, how the technology works to collect the data, or how this technology/evidence has been used in other applications.
Review the Discussion guidelines