When is the next Solar Maximum?
GRAPHING SUNSPOT ACTIVITY

CONCEPT

Sunspot activity is directly related to the frequency of major solar storms. It is important that we know when these major solar storms are likely to occur because they can cause electrical blackouts, communication outages and satellite problems here on Earth. This is referred to as "Space Weather" forecasting. Using historical sunspot activity data, you will try to find a pattern of activity in the number of sunspots that have been observed since 1900 and then predict when the next maximum sunspot activity will occur (solar max).

VOCABULARY

Sunspot - a dark spot on the sun's surface caused by the cooling of the sun's surface by very intense magnetic fields.

Sunspot Number - the number of sunspots that can be seen on a given day varies greatly throughout the year. Usually the daily numbers are averaged over a period of one month, and this monthly average is referred to as the sunspot number. These monthly averages can then be averaged for a whole year to give the yearly sunspot number. (In practice, it is a little more complicated that this, as individual sunspots, and sunspot groups, are counted differently.)

Sunspot Cycle - the average length of time between maximum sunspot activity.

Maximum and Minimum - when a graph shows the highest and lowest values for a variable that is measured over a period of time.

OBJECTIVE

Students will use graphing techniques to analyze historical sunspot activity and try to identify patterns in the data that will identify the maxima and minima of the sunspot cycle. They will then use this data to predict when the next maximum will occur and what the average number of years between maximums is for sunspot activity.

MATERIALS

• graph paper
• pencils
• sunspot activity data

1. Tape two or three pieces of graph paper together so that there will be at least 105 data points on the x-axis. Label the x-axis from zero to 110, representing the year 1900 to 2010.
2. Label the Y-axis from zero to 200. (Increments of 5 for each line on the Y-axis.)
3. Have the students plot the sunspot activity from 1900 to 1999.
4. Connect all the data points on the graph and observe the resulting pattern.
5. Measure the number of years between each peak value.
6. Find the average number of years between the peaks by adding up all the numbers in step 5 and dividing by the number of values you used.
7. Forecast the year that the next maximum sunspot activity will occur by adding, the average number of years between peaks calculated in step 6 to the last known peak on the graph.

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