Measuring the Size of the Earth from Arizona

Kéyah Math Project development team: Nancy Zumoff, Christopher Schaufele, Steven Semken, Tracy Perkins, Lynn Onken, Philippe Laval, David Gonzales, and Andrew Becenti (deceased).
Kéyah Math Project directed by Steven Semken , Arizona State University; and Christopher Schaufele and Nancy Zumoff, Professors of Mathematics, Emeritus.
Archived at Arizona State University School of Earth and Space Exploration.

Summary

In this activity, students use the geometric method of Eratosthenes and geographic data from Arizona to estimate the circumference of the earth. The circumference is then used to compute the radius and volume of the Earth.

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Learning Goals


Objectives
  • Use the geometric method of Eratosthenes with geographic data from Arizona to estimate the circumference of the Earth.
  • Use the result to compute the radius and volume of the Earth.

    Mathematical Skills
  • Use the geometry of a circle (radius and circumference) and a sphere (volume).
  • Calculate interior angles.

    • Context for Use

    This activity consists of a set of quantitative problem-solving exercises that can be used as an in-class activity or an assignment in any introductory geology, geography, or Earth and space sciences course.

    Description and Teaching Materials

    Teaching Notes and Tips

    An Instructor's Guide to all Kéyah Math activities is available online from the Instructor Resources page on the Kéyah Math website.

    Assessment

    Students record their work and answers in a word-processor document or a notebook, which can be submitted to the instructor for assessment. Solutions to these problems are available online from the Instructor Resources page on the Kéyah Math website.

    References and Resources

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