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Sun Spot Analysis

Activity and Starting Point page by R.M. MacKay. Clark College, Physics and Meteorology.

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This page first made public: May 11, 2005

This material was originally created for Starting Point:Introductory Geology
and is replicated here as part of the SERC Pedagogic Service.


Introductory students use Excel to graph monthly mean Greenwich sunspot numbers from 1749 to 2004 and perform a spectral analysis of the data using the free software program "Spectra". Short answer and thought questions related to the graphical data are asked throughout the assignment.

Learning Goals

Context for Use

This activity is useful in any introductory geoscience course in which a discussion of the solar cycle is appropriate or in which an introductory exposure to Fourier spectral analysis is desired.

Description and Teaching Materials

The assignment in a form that can be printed and handed out to students is:

Teaching Notes and Tips

The two graphs above show essentially the same thing. The graph on the right was made with Excel by importing the Text frequency data from the Text output Window of Spectra. The Spectra program does not allow you to alter the horizontal axis. We did not ask students to do this step in the assignment since they can read the numerical values from the graph or from the table, but you may want to use these two figures in a follow-up discussion.


The successful completion of this activity and evaluation of their results are good measures of student comprehension. Follow-up discussions in class, essay questions on exams, and the future success of students on other related activities are also useful measures of student understanding.

References and Resources