Download - Stevenson High School

Solar Astronomer: ______________________
Mr. Gord
Astronomy
Date: ________ Hour: __________
Sunspots Revealed!
Background: In 1611, Galileo wrote about dark spots that he observed on the face of the sun with his telescope.
Some of these spots, now called Sunspots, last only a day or two. Others are observed for as long as a month. Galileo
noticed that the longer lasting spots seemed to move in unison across the face of the sun. He concluded that this was
due to the rotation of the sun.
Sunspots are believed to be the centers of great magnetic storm in the gases on the sun. They appear to be
dark because their temperatures are lower than those of the surrounding gases. Since 1749, scientists have kept
records of the number of sunspots observed each year. Some of these data will be used in this investigation. You can
study both the short-range and long range patterns that are a clue to the activity going on in the sun. Whenever a
pattern repeats itself, it is called a cycle. See how many different kinds of sunspot cycles you can find as you plot the
graph in this investigation.
Procedure:
1. Obtain the Sunspot Activity graph. This is real data from 1750-1966.
2. Study the graph. You should notice a pattern. The number of sunspots increases and decreases throughout the
years.
3. QUESTION: Is the occurrence of sunspots predictable? Explain your thoughts with complete sentences. Do
not start your sentences with the word “it” or “they”.
4. Choose a colored pencil and circle (highlight) each sunspot maximum (the peaks) with the colored pencil.
Should you circle the dot at year 1750? 1966? NO! Even though it is a high point on the graph it is not
certain to be a MAX because you don’t know the year before 1750 or the year after 1966. From one Sunspot
Maximum to the next Sunspot Maximum represents one cycle. Also do not circle 1864. Do not circle 1802
and 1804, just circle one of them. Same for 1883-4 and 1905-07.
5. QUESTION: How many sunspot cycles are there during the time that the data was taken? __________
6. The number of years between two successive colored dots represents the time of the cycle. Count the number
of years between each consecutive Sunspot Maximum. Write that number on the graph between the two
Sunspot Maximum Dots.
7. Now calculate the average length of one cycle by dividing the total number of years by your answer from
QUESTION 5 above.
Number of years from first max until last = ____________ ÷ by your answer from above =__________
Average length of the one cycle = ____________
Round the average to nearest whole year and write that value here = ___________________
8. Use the rounded value that you determined to calculate the next year that the sun will have another peak.
Don’t forget the current year is ____________. Your data only goes up to 1966. There are probably several
peaks that will have occurred between 1966 and now. I am asking you to calculate the next time we will
experience a SOLAR MAX.
The Next Solar Max will be ________________