ACTIVITY 2: SUNSPOT NUMBER VARIATIONS

Transcription

1 ACTIVITY : SUNSPOT NUMBER VARIATIONS Saturn and its Moons QQQ Its orbit around the Sun Other factors affecting and mass ;;;density Guide to Teachers Goal: Students learn about sunspot variations and the solar cycle, and are able to predict future solar minimums and maximums. This activity focuses on one feature of the Sun seen in the last activity, sunspots, and examines their variation over times much greater than a solar rotation (about days). It functions as an EXPLORE phase in Solarscapes MATERIALS NEEDED One copy of the student activity information and worksheet (included) Table of yearly sunspot numbers (Charts # and #, included) A photocopy of the student activity, preferably one copy per student. Provide the worksheet first, then the rest of the text once students have discussed their initial ideas Three sheets of graph paper per group of students Colored pencils Ruler Scissors Teacher Guide, Activity : Space Science Institute,. All Rights Reserved.

2 Procedure: XXXXXXXXXXX XXXXXXXXXXX XXXXXXXXXX DISCUSS: Students discuss what they know about sunspots and their variations. This allows them to revisit some material from Activity. Many may know that the number of sunspots changes over time, or even that the number changes in a regular cycle. Students then report a few ideas from their groups, facilitated by the teacher. EXPLORE: Provide students with activity materials and text. Students work in groups of three. They begin by reading about sunspots and their relationship to Earth. Each student prepares a graph using the procedure in the student worksheet. They plot the number of sunspots for each year using Charts # and #, join their graphs and observe the resulting pattern. The teacher should assist students who are having difficulties producing a correct graph of the data to ensure that all students who wish to produce a correct graph do so. NOTE: Since they will be taping these graphs together, make certain that all three students in each group use the same scale for both the time in years (x-axis) and sunspot numbers (y-axis). REFLECT: At this point, the teacher should call on several students to report their observations. After discussing the observations, tell them that the pattern they see is called the Solar Cycle. Solar cycles have been numbered beginning with the minimum that occurred about. A cycle includes an increase and the following decrease in sunspot numbers. Cycle number peaked in 0. The next two sunspot cycles are numbered and. Students are to number the cycles on their graphs. Point out to students that during the Maunder Minimum (from to ), the solar cycle almost disappeared as no sunspots were seen. The link between climate (long-term variations in the weather) and sunspots may have something to do with the maximum number of sunspots in a cycle, but scientists do not completely understand the connection. APPLY: Students use their graphs to answer various questions and predict aspects of the next sunspot cycle. Options for modifying this activity: As it is written, the activity for plotting sunspot numbers takes a class of 0 students, who meet in minute periods, about three or four days to complete. To reduce the amount of time that you spend on the activity to about two days, you might try the following suggestions Have the students only plot every other point. Assign students to finish plotting the data as homework. For smaller classes (fifteen or less) and for an activity that gets students out of their seats and moving about, you might try the following procedure: Teacher Guide, Activity : Space Science Institute,. All Rights Reserved.

3 Use butcher paper long enough to graph the accompanying data (perhaps cover one wall of a classroom).. Prepare the butcher paper in advance by drawing the horizontal axis along the bottom and labeling it Time in Years. from 00 to present. Draw a vertical axis on the left hand side of the butcher paper and label it s. from to 00. Write a title.. Cut out the individual dates or series of dates for individual students to graph.. Have students graph the sunspot numbers that you have prepared. (This is most exciting when students have sunspot numbers that are not sequentially, but randomly dated so that they must move around to find the dates on the horizontal axis.) When all of the points are plotted, have several students connect the data points.. Ask students to observe the resulting pattern, answer the questions that accompany this activity, then draw their prediction for the next two sunspot cycles on the graph using a dashed line. Explore More: To add an interdisciplinary or a personal touch, ask students to mark historical events or dates of personal interest such as birthdays. Teacher Guide, Activity : Space Science Institute,. All Rights Reserved.

4 Scoring Rubric for Activity : Student Name: Individual Assessment (goal met if student achieves a "") Task(s) 0 Answering questions and making predictions Student did participate questions. not or answer Student answers questions, but is unable to explain answers. the Student answers questions, includes reasonable explanation for those answers, but does not provide a reasonable prediction for sunspot cycle numbers and or a reasonable explanation for the answer. Student answers questions, includes a reasonable explanation for those answers, but does not provide a reasonable prediction for sunspot cycle numbers and. Student does all of the things in "," but also includes very innovative answers for question. Group Assessment (goal met if group achieves a "") Task(s) 0 Producing a graph of sunspot numbers and making predictions Group does not produce a graph. Group produces a graph that does not contain reasonable predictions for the sunspot cycle numbers and. Group produces a graph that does contain reasonable predictions for the sunspot cycle numbers and. SUGGESTED USE: Make one copy per student; there is also room for you to add your own task and scoring criteria. Teacher Guide, Activity : Space Science Institute,. All Rights Reserved.

5 Student Guide to Activity : Problem: What pattern(s) emerge when sunspot numbers are plotted over a period of time? Introduction A student s dream comes true! On a quiet, mild, mid-afternoon, the overhead lights flicker just a little. A few minutes later, the same lights dim faintly, then suddenly all is dark. A hoot of delight reverberates throughout the school as students hopes for an unexpected vacation rise. What happened to cause this sudden surprise? If you live in the north, perhaps it was due to a sudden snowfall or sleet storm. If you live in the south, maybe it was a power overload on a hot day. But, this is a mild, quiet afternoon. What could cause a dramatic power outage? Just a few short decades ago we would never have suspected that our ultimate energy source, the Sun, was the culprit! How could that be? That reliable sphere of glowing gas that rises daily in the east and sets in the west sends us visible light that arrives on Earth after about minutes of travel through space. Besides its dazzling brightness, the Sun s next most obvious features are the appearance of dark, cool areas called sunspots that can be seen when the Sun s image is projected onto a piece of white cardboard through a pin-hole (never look at the Sun directly!!). s are huge magnetic field bundles that are shaped somewhat like a horseshoe magnet. These magnetic fields result in cooler, darker regions on the surface of the Sun that we see as sunspots. s are sources of a tremendous amount of energy including solar flares, the most violent events in the solar system. In a matter of minutes, a large flare releases a million times more energy than the largest earthquake. Auroral curtains photographed by astronauts on NASA s STS- mission (courtesy of NASA) s and the resulting solar flares affect us, here on Earth. In fact, the more we learn about sunspots and solar flares, the greater their influence on Earth appears to be. Solar flares emit radiation that includes X- rays and ultraviolet rays, and charged particles called protons and electrons. This radiation surge may damage electrical power systems, interfere with telecommunications, disrupt high-tech ship navigation systems, harm an astronaut in space, or create the spectacular aurora (Northern and Southern lights). Student Guide, Activity : Space Science Institute,. All Rights Reserved.

6 Currently, scientists at NOAA s Space Environment Center in Boulder, Colorado, conduct research in space physics and develop new techniques for forecasting solar events like solar flares. The Space Environment Services Center is the national and world warning center for these disturbances, called space weather. Space weather affects both people and equipment not only in airline and space travel, but also in Earth-based jobs such as long-line telephone communication systems, pipeline operations, and electric power distribution. Space Environment Forecast Center (courtesy of the Space Environment Center, NOAA) Through years of study, we now know that the chances of a sudden surge in radiation on Earth caused by a solar flare is related to an increase in the number and complexity of sunspots. Therefore, researchers plot average sunspot numbers over a period of time so that we know when to expect the next series of disruptive, potentially dangerous solar flares. The sunspot number (also called the Wolf number after Rudolph Wolf, who devised the method) is not actually the number of sunspots on the Sun. It is calculated with a formula that does depend on the number of visible sunspots recorded at selected observatories around the world. Another mysterious connection between sunspots and life on Earth has to do with climate. During a period from to known as the Maunder minimum, almost no sunspots were seen. During that same time, Earth s Northern Hemisphere experienced the Little Ice Age as average temperatures dipped and rivers froze. What is the connection? Scientists are not certain, but sunspots must be telling us something important about how the Sun works and produces energy. Thus, as our knowledge of the interaction between the Sun and Earth improves and our use of the space environment increases, space weather forecasting becomes more important. Although we may feel, see, or hear nothing Europe experienced a Little Ice Age in the seventeenth century. This painting, Skating/ Frozen River, recorded by Hendrick Avercamp is of an unusual freezing of Dutch canals. unusual, our electrical power may fail, our telecommunications may falter, and satellites may no longer function. Some people may speak of mysterious, superstitious forces, but we know that none other than our closest star, the Sun, is the culprit. And in the long term, studying sunspots could help us solve the many mysteries of our nearest star mysteries that could mean life or death for planet Earth. Student Guide, Activity : Space Science Institute,. All Rights Reserved.

7 Procedure: ACTIVITY STUDENT WORKSHEET. Working in groups of three, read the text for this activity. XXXXXXXXXXX XXXXXXXXXXX XXXXXXXXXX. When all of you are done reading the text, obtain three sheets of graph paper (one for each of you), colored pencils and a ruler from your teacher. Each of you will now complete a graph. NOTE: Be sure to agree beforehand on what scale you will use (for example, each vertical line might represent year), because you will be taping these together once all graphs have been completed. Use your ruler to Draw a horizontal line (x-axis) along the bottom and label it Time in Years. One student will number his or her graph from the year 00 to the year. Another will label the second graph from 00 to. The third student will number the third graph from 00 to 00. Draw a vertical line (y-axis) along the left hand side of the paper and label it s. Counting by tens, number from 0-00 sunspots. (Do not skip lines.) Again, be sure that all three of you use the same scale.. Plot the number of sunspots for each year using Charts # and #. Connect the data points with a continuous solid line. Observe the resulting pattern in your graph and record your ideas in the space provided.. When each of you completes the graph, tape together the three graphs (put the tape on the back of the paper) so that the graph represents a time line from 00 to 00. NOTE: Tape your graph together so that the time line is continuous, i.e. with no breaks. One or more of you may need to cut off the part of the edge(s) of your graph in order to accomplish this. Student Guide, Activity : Space Science Institute,. All Rights Reserved.

8 Discuss the pattern with your group and record your ideas in the space provided, along with a sketch of your group s graph. Be prepared to share your ideas with the class. Sketch NOTE: cycles have been numbered beginning with the minimum that occurred about. A cycle includes an increase and the following decrease in sunspot numbers. Cycle number peaked in 0. The next two sunspot cycles are numbered and.. Beginning with the sunspot maximum about year, number each sunspot maximum directly above the line graph.. Using a dashed line , draw your prediction for the next two sunspot cycles on the graph (i.e. cycles and ).. In the space provided, compare what you now know about sunspots and their variation to what you knew when you started this activity.. What pattern(s) emerge when sunspot numbers are plotted over a period of time? Student Guide, Activity : Space Science Institute,. All Rights Reserved.

9 Answer the following questions and explain your answers:. What is the average time between the high points (periods of maximum sunspot activity)?. Predict the years for the next two sunspot maxima (sunspot cycle numbers and ). Show your work.. Predict the years for the next two sunspot minima.. Predict how many sunspots there will be in the year that you graduate from high school.. What additional patterns do you see when you observe data over a long period of time compared to observing data for the shorter period of time? (For example, compare the individual graph that you made for the 00 year time period to the larger graph.). Why is it important to collect and to study data over a long period of time before drawing conclusions? Give an example other than sunspot data. Student Guide, Activity : Space Science Institute,. All Rights Reserved.

10 Explore More:. Explain (tell why you came up with) your prediction for the years of sunspot maxima (cycle numbers and ).. Predict how large sunspot cycle numbers and will be. Explain your prediction.. Predict the shape (on the graph) of the next sunspot cycle (). Explain your prediction. Student Guide, Activity : Space Science Institute,. All Rights Reserved.

11 Year Year Chart #: 00-0 Year Year 00 M m M. M M m m m m 0. M M M. m M m m. M. m.... M M m M m 0. M m m. M Student Guide, Activity : Space Science Institute,. All Rights Reserved.

12 Year Year Chart #: - Year Year m M 0. m. m. M M 0. M.. m m. M m m. 0. M M 0.. M. 0.. m M m m. m M.. M. 0.. m M M m.. Each "M" marks a sunspot cycle maximum and each "m" is a minimum. Through, yearly means were calculated as the average of the monthly means; since, yearly means have been calculated as the average of the daily means. Student Guide, Activity : Space Science Institute,. All Rights Reserved.