Lesson: Differential Rotation of the Sun

(Grades 9-12)

Teacher Information

The Sun has a north and south pole, just as the Earth does, and rotates on its axis. However, unlike Earth which rotates at all latitudes every 24 hours, the Sun rotates every 25 days at the equator and takes progressively longer to rotate at higher latitudes, up to 35 days at the poles. This is known as differential rotation.

The Sun rotates in the same direction as Earth. The Carrington Rotations are named for Richard Carrington, an astronomer who first noted that sunspots rotate every 27.28 days. Rotations are numbered starting with 9 November 1853. The 1996 Jun 18 - 1996 July 15 rotation is rotation number 1924.

This lesson uses SOHO data from the EIT(Extreme-ultraviolet Imaging Telescope) instrument on the spacecraft.

Activity: Longitude and Latitude

(Students become familiar with locating positions on a sphere, appropriate for grades 9-12)


Type of Activity:


  1. Review longitude and latitude
  2. Make connection from Earth to Sun.
  3. Given a seven day sequence of EIT images, students plot two active areas on a solar grid.
  4. Independent Student Research: Students study images of the sun for a period of 2 - 3 months, track active regions at different latitudes, and calculate differential rotations.

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Connections to National Standards:

Created by: Ginger Sutula
Direct comments to: vsutula@umd5.umd.edu