Graphing Sunspot Cycles

An activity adapted from Rice University-Houston Museum of Natural Sciences, Summer Solar Institute, Being a Solar Astronomer

Type of Lesson: Investigation with evaluation worksheet

Time Needed: 90 minutes (or 2 class periods)

Standards Addressed

MEGOSE ES5 Describe and explain common observations of the day and night skies.
MEGOSE ES7 Compare our sun to other stars and star systems.
MEGOSE ES8 Explain common observations of the day and night sky.

Quick Summary of Lesson

The student will be able to determine existing patterns in sunspot numbers.
The student will be able to plot sunspot numbers to determine these relationships.
The student will be able to use these relationships to determine the approximate number of sunspots for a year in the near future.


sunspot numbers (available on Student Activity Sheet down below)
graph paper


1. Have students complete the sunspot plot for the table of sunspot numbers given on the student worksheet.

2. Students should then complete the questions on the student worksheet. It might be helpful to lead a discussion concerning the questions.

Student Activity Sheet

Please click here for student activity sheets. All activities on the Windows to the Universe site may be printed and reproduced if being used for educational purposes.

Notes to the Teacher

If students are graphing all of the given sunspot numbers, it will likely take them more than an hour to graph. They can get a good feel for the solar cycle and answer the questions on the student worksheet by just graphing a subset of the given sunspots. If you want to take less time to do this activity, have students graph from 1850 to present.

An example of the sunspot plot your students should come up with appears here. You'll see the labelling of the maximums with "M" and minimums with "m". There is of course a regular pattern of sunspot numbers. Scientists say the sunspot cycle is 11 years long. The average your students should get from the years represented in this table is 10.84. The year 2000 was a solar maximum. The year 2011 should also be a solar maximum making 2006 and 2015 close to a solar minimums.

Sunspots have been known and recorded for hundreds of years. The reporting techniques have not always been consistent. Currently we can determine the average number of sunspots appearing each day. The yearly number is the annual average daily sunspot number. It is highly instructive to determine the nature of the cyclic characteristics of sunspot numbers. A large number of natural phenomena have been related to sunspots (or the periods of great numbers or few, etc.). A new area of scientific research called spaceweather has been formed to try and explain these Sun-Earth connections.

Need More Information? Try Using Windows to the Universe

Please use these links for further ideas or more information:
The Difference Between the Sun and Other Stars
The Photosphere
Plotting Sunspots another classroom activity
Solar Activity
The Solar Cycle
The Sun
Tracking an Active Region another classroom activity