Grade Level/Subject
Unit
Enduring
Understanding
SOL Objectives
11th/12th Astronomy
The Sun
Dynamic finite processes occurring in and
around the Sun are responsible for creating all
forms of electromagnetic radiation, and drive
processes occurring on Earth and the forms of
life that inhabit it.
SOL 6.8 - The student will investigate and
understand the organization of the solar system
and the interactions among the various bodies
that comprise it.
d) revolution and rotation;
Title
Lesson Objective
Sun Spotting


Inquiry Level
Sun spots are dynamic phenomena on the
sun
The sun rotates at different rates at
different latitudes (differential rotation)
3 – Question given, methods open, solution
open

Materials Required


Telescope with solar filter (Mylar or
otherwise) or Binoculars and stiff screen
to project images on
Stiff piece of white poster board, roughly
8”x11.5” for the projector screen
Magnetic Compass
Sun Spotting
In this lab, we will be investigating the motions of
sunspots across the surface of the sun.
1. Before starting this lab, how do you think
sunspots move and change across the
surface of the sun?
2. What could cause sunspots to move on
the surface of the sun?
Sunspots on the Sun as seen by SOHO
Source: NASA.gov
3. Looking at the sunspots in the image at the upper right, what do you notice about the size,
clustering, and location of sunspots.
a. Size:
b. Clustering:
c. Location:
4. If the sun had a solid surface as the earth does, how do you think sunspots would then
move?
5. Knowing that the sun is more like a liquid, how do you think sunspots could move?
6. Do sunspots near the equator have a larger distance or smaller distance to travel compared
to sunspots at 45 latitude (halfway to the northern pole)?
Create a sunspot viewing station
CAUTION: Looking directly at the sun can cause serious eye damage, even blindness. NEVER
look directly at the sun. Never use binoculars to look at the sun.
Follow the instructions at the following website to setup your sunspot viewing station.
http://spaceweather.com/sunspots/doityourself.html
Once you have obtained an image, identify sunspots. Place your sun coordinate grid under your
image so that the north (N) is pointed towards cardinal south according to your compass. Images
that project onto screens are inverted, so we have to flip our axes to better line up our sun’s image.
Identify sunspots by numbering them. They will persist for a couple of days to weeks, so be sure
you can identify the same spot day-to-day.
Under Sunspot ID, insert the identifier you assigned to your sunspots. Under Day #, insert the date
(for instance, 3/17 for March 17th). And at each day and sunspot, record the latitude and longitude.
For instance, Lat: 15 N, Long 10 W. You should try to get seven data points for each sunspot.
Some months, there may be very few to no sunspots, other months there may be dozens. Try to
identify the most evident ones.
Sunspot Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7
ID
_______ _______ _______ _______ _______ _______ _______
For each Sunspot listed in your table, plot the data on a separate piece of graph paper with the axes
listed below. Plot each sunspot in a different color and make a legend so that they are easily
identifiable. Make sure to properly label your axes, include units, and a title.
1. Plot Longitude versus time
2. Plot Latitude versus time
Note four trends that you see in your graphs.
1.
2.
3.
4.
By looking at sunspot movement, astronomers can pinpoint the rotation rate of the sun. Estimate
the rotation rate at different latitudes from your data. For instance, if you notice that one sunspot
moves from longitude 30 E to 20 W in 3 days, we can estimate the rotation rate using ratios:
𝑡
360°
=
3
50°
Therefore, 𝑡 = 21.6 days for one complete rotation.
Use this information to fill in the table on the next page. Be sure to order your data from lowest
latitude to highest.
Latitude versus rotation period of the sun
Latitude ()
Rotation Period (days)
Discuss any trends you see in your data.
From your data, does the sun seem to rotate like a solid (like the earth), or is there another type of
rotation that appears to be happening?