Activity 1.12 Plate Tectonics and the Scientific Method (Grades 9-12)

The development of the plate tectonic theory serves as an excellent example of the scientific method. After presenting the history of the plate tectonic theory, ask your students to write a short essay on the scientific method as exemplified by plate tectonics. Their essay should include some of the points listed below.

The scientific method is a series of steps that can lead to the discovery of new scientific principles. The steps are:

  1. Gathering a set of observations or measurements (a data set) from natural phenomena or experiments.

  2. Formulating one or more hypotheses to explain the observations or data. The hypotheses can be conceptual, physical, or mathematical. A hypothesis is unproved and must be testable.

  3. Making a set of predictions using the hypothesis. The predictions are then tested. If the predictions are correct, the hypothesis gains credibility. If the predictions are incorrect, the hypothesis must be modified or abandoned. The hypothesis is modified and retested many times before they can account for all the data.

  4. Gaining the status of a theory after being tested by new experimental advances. A theory is a generally accepted explanation for a set of data or observations.

Reexamine the Teacher Background. How does the development of plate tectonics follow the scientific method?

  1. Wegener gathered sets of observations on the distribution of rock types, fossils, glaciation, and climate zones. He searched for a common explanation to relate these diverse features and phenomena.

  2. Wegener hypothesized that the present-day continents were in different positions in the geologic past. By reassembling the continents into a single supercontinent, he explained the distribution of rock types, glaciation, and fossils. The drift of the continents over the surface of the Earth with time explained the distribution of climate zones.

  3. Wegener also proposed that continents plowed through oceanic crust. However, other geologists knew this to be impossible because of the strength of rock. Wegener's hypotheses, although satisfactory in many respects, could not explain all the observations. It was not until new methods of testing continental drift (and sea floor spreading) were introduced that plate tectonics gained acceptance. For example, it was predicted that the age of rocks increased away from mid-ocean ridges. Dating methods for rocks proved this prediction true.

  4. Plate tectonics has been rigorously tested from numerous subdisciplines in geology. Most geologists accept these tests as verification of plate tectonics. Successful testing and widespread acceptance elevates plate tectonics from a hypothesis to a theory.

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