The magnetic North pole is the point to which the needle of a compass points. The magnetic North pole is not in the same place as the 'real' North pole, the point where the (imaginary) rotational axis of the earth sticks into the ice. The magnetic pole wanders all around the northern wastes, and it is in a different place from year to year. Here is a map of where the magnetic pole has been since 1831, and another map that goes from 1600 to 2000. ![]() |
How to set up the sunspotter: |
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How to point the scope at the sun: |
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![]() The same can happen in the vertical direction. |
How to take data: |
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How to analyze the sunspot data: |
STEP 1: Take your index cards and see if there is one particular sunspot that you can follow over several days. Use the pantograph to enlarge the sun's image, and to copy all locations of the spot onto one sheet of paper. By each dot, copy the date. | ![]() |
STEP 2: Find the middle of the sun's outline, and with a compass draw a nice circle over the outline you traced with the pantograph.
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STEP 3: Draw a line that roughly goes through all the points, and then draw a line perpendicular to the first one, and also goes through the middle of the sun.
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STEP 4: Off to the right, draw a circle with the center on the last line, and with a radius equal to the sun's outline you drew in step 2. This is the sun as if you are looking down at it from the top. Now draw a line parallel to the last one, and that goes through the point where the the sunspots would disappear around the side of the sun (by the arrow) Draw a smaller circle that just touches this line. This smaller circle is the path that the sunspots would follow if we were looking down on the top of the sun.
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STEP 5: Now draw a line parallel to the main axis, from the first sunspot to where you just cross the small circle. Repeat for all other sunspots. | ![]() |
STEP 6: Here I have shown the right-hand side of the sheet, and rotated it such that the last lines that you drew are shown coming from the top. Where those lines intersect the small circle is where the sunspots would be if you were looking at the sun from the top. Draw a line through the center of the circle. The orientation does not matter much. Then draw lines from the center to each of the intersection points. | ![]() |
STEP 7: Now get out your protractor and measure the angle between the big horizontal line and each of the lines you drew from the center to the sunspots. Make a table of this angle and the date and time when you observed this sunspot. Make a third column showing how much the angle changed since the previous day. |
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STEP 8a: For the final step, there are a few options. This paragraph is for those grades where the kids are supposed to be able to plot graphs. In this version, we will plot the angle (column 2) versus the date/time (column 1). Then we'll read off the rotational period from the graph. (...more..) |
STEP 8b: For the final step, there are a few options. This paragraph is for those grades where the kids can't make the graph like we did in 8a. Instead we will calculate how many degrees the sun moves per day, on average, and get to the rotational period from there. We'll use the numbers in column 3 for this. (...more...) |