Cycles of the Sun and Moon

John McDaris
Author Profile
Initial Publication Date: September 26, 2007


This activity asks students to download sunrise and sunset data along with moon phase data and graph these data sets together in a spreadsheet in order to visualize the cycles of the seasons and the moon.

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Learning Goals

  • Provide students experience with downloading real-life data from the internet.
  • Show students how to use a spreadsheet program to graph data sets.
  • Stimulate students' analytical thinking by asking them to interpret the patterns that are present in the final graphs.

Context for Use

This activity is appropriate for students in high school and lower division undergraduate earth science classes. Students should be familiar with sine and cosine functions and a spreadsheet program such as Excel.

Depending on class length, this activity should take one to two class periods to complete, or could be begun in one class period with the students left to finish the remainder as homework.

Description and Teaching Materials

Part 1 Activity Sheet (Microsoft Word 570kB Feb17 06)
Part 2 Activity Sheet (Microsoft Word 648kB Feb17 06)
Part 3 Activity Sheet (Microsoft Word 348kB Feb17 06)

Teaching Notes and Tips

The activity is split into three parts. Of these three, the second will probably prove the most challenging as it requires students to fit the set of moon phase data to a sine or cosine curve via trial and error. Some help with this step is provided in the activity sheet for Part 2.

The activity sheets are written assuming that the data will be downloaded from the Naval Observatory website. If another data source is used, the activity sheets will need to be updated with the proper instructions for downloading the data.


Each student will produce several graphs including one of the combined data sets. These should be similar across the class even if students use data sets from different years. There are also some questions for students to answer as a part of one of the activity sheets. Students must interpret the graphs they have created in order to answer these questions.

References and Resources

US Naval Observatory Data Services (more info) : This site provides links to many different data types that are provided free to the public by the US Naval Observatory. Data types include: sunrise and sunset, phases of the moon, eclipses, solar system boy information, dates, and celestial navigation data. Data is available for a wide variety of time periods and locations.

Universe Now: This website provides data on day length. There are fewer options in terms of additional information and moon phase data are not available, but the interface is very easy to use and intuitive. This site may be more appropriate for younger students.