Lesson 3: Tracking and tracing sunspots


This activity will require approximately three 30-minute classes

  • 1 class period to introduce the concept of sunspots and the Tracking Sunspots applet
  • 1 class period for the students to work with the Tracking Sunspots applet
  • 1 class period for the closure activity using binoculars and white paper to observe actual sunspots


Identify and use a variety of sources and technologies to gather pertinent information (e.g., use electronic and print resources or visit a planetarium to gather information on the visual characteristics of planets)
Compile and display data, by hand or by computer, in a variety of formats including frequency tallies, tables, and bar graphs (e.g., prepare a diagram showing the orbits of the planets)
Draw a conclusion, based on evidence gathered through research and observation, that answers an initial question (e.g., conclude that simulated flour craters are deeper and wider when the marble is heavier or is dropped from greater heights)

General Objectives

Work in groups of two using the Tracking Sunspots applet to determine the axial rotation rate of the Sun. Learn that the surface of the Sun is not solid, but rather a turbulent mix of gas, thus exhibiting differential rotation (some parts of the Sun rotate faster than others). Learn of the connection between sunspots and Northern Lights.

Curricular Connections

  • Information and Communication Technologies
    • Using interactive applet
  • Visual arts
    • Sketching sunspots

Lesson Overview

In this activity students will be using the Tracking Sunspots applet to investigate sunspots and the movement of the sunspots across the surface of the sun. Student will use the functionality of the applet to determine both linear and angular approximations to the rotation of the Sun. Through their investigations, students should be able to identify differential rotation. Students will also use the applet to determine the size of the penumbra and umbra of sunspots.

Materials and Resources

Nota : This page contains documents for which the access may require a particular software. If the software is not installed, you can download it and follow the instructions for installation.


  • sunspot
  • umbra
  • penumbra
  • differential rotation
  • solar flares
  • photosphere
  • corona

Developing the Lesson

Before commencing this lesson, teachers should become very familiar with the applet to ensure that they will be able to assist the students should the need arise.

  1. The lesson should begin by briefly introducing students to sunspots
  2. Students should be made aware that Galileo was the first person to discover sunspots in 1610
  3. The teacher should also explain that sunspots occur on the surface of the Sun and can therefore be used to determine the rotation rate of the Sun
  4. After briefly introducing the concept of sunspots, the teacher should then explain that in this activity students will be using an interactive applet to observe and track sunspots on the solar surface through which students will determine the rotation rate of the Sun
  5. The teacher should also walk students through the procedures they will be expected to perform with the applet and also how the students are to fill in the worksheet.
    • Teachers might wish to print out the student version of the Using the Applet handout.
  6. The teacher will assign students to groups of 2 and will dismiss the groups to begin working with the applet
  7. The teacher should monitor students progress with the applet and be prepare to assist when students are having difficulties
  8. Once students have had sufficient time to work with the applet, the teacher should reassemble the class and begin the closure discussions


Reassemble the students and initiate a discussion as to the findings the students were able to interpret from their work with the applet. The teacher should then lead a discussion based on the following questions. Were all students able to detect differential rotation? Did students obtain significantly different results between linear and angular calculations? What was the largest sunspot the students identified?


Possible Marks 6 4 2 0
Working with the applet Excellent participation and group work Level of participation was adequate Little evidence of work Student was off-task most of the time
Completed WebQuest activity sheet Evidence of excellent research WebQuest is missing key components WebQuest is of poorer quality Evidence of very little if any research
Explanatory paragraphs Paragraphs are very well written and offer insightful explanations Paragraphs are decently written and explanations offer some insight Paragraphs are poorly written and explanations offer little or no insight Paragraphs were not done