Exploring the Sun The Differential Rotation of the Sun

Link to the demonstrator: in English


Age: 14-17

Duration: 3 hours

Equipment: PC with internet connection 

Contact details                                           

Author: Dr. Rosa Doran (NUCLIO)
Contact: info[at]frontiers-project[dot]eu



This demonstrator introduces the Sun as an active star and how its activity can influence Earth. Students are questioned about its movements and led to realize that the Sun rotates. Real images will be used to determine the solar rotation period. Students will learn how to use a specific image software to track sunspots and calculate the Sun’s rotation period. Further analysis will show that the Sun doesn’t rotate as a rigid body: it exhibits differential rotation. Students can present their work to the class and discuss how they compare with the most accurate results that astronomers have.


Learning outcomes:

  1. Teach students about the Sun’s activity and its influence on Earth.
  2. Allow students to understand the evidence of the Sun’s rotation movement.
  3. Introduce basic concepts of Astronomy and Image Processing.



Prior knowledge:

  • Basic Astronomy knowledge of the Sun as a star
  • Excel (charts)
  • Kinematic’s concepts such as: period

Concepts introduced:


  • Sun’s activity
  • Sunspots



Learning intentions:

By the end of this descriptor, students should be able to:

  • Describe the Sun as an active star
  • Explain what sunspots are
  • Describe a method to measure the rotation period of the Sun 
  • Examine images using the salsa J software
  • Form conclusions about the Sun’s differential rotation


Key activities:

  1. Videos to engage 
  2. Salsa J – making movies and examining images
  3. Different methods to measure the rotation period of the Sun
  4. Analysis and explanation 
  5. Final report and discussion



By the end of this descriptor, students should be able to answer the following: 

  1. Write a couple of sentences describing what you learned about the Sun’s activity.
  2. What movements does the Sun have? How can we prove that the Sun rotates?
  3. How do we know that the Sun rotates differentially?
  4. Why doesn’t the Sun rotate like a rigid body?

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