Science Buddies: "Ask an Expert"

Hi. I am doing this project on the topic "Do sunspot cycles have a faster rise time and slower decay time?" I have reached the part where I have to calculate the onset and decay time but the information given on sciencebuddies seems a little vague. It only says "Now you have all the information you need to calculate the onset and decay time for each solar cycle.With what you've learned about spreadsheets so far, you should be able to do this on your own." I know that I have to just subtract the time of beginning, peak and end of each cycle.But I am confused because the data I have now consists of only no. of monthly and smoothed monthly sunspots and the date in fraction of year for the middle of corresponding months. What should I do to find the time of beginning, peak and end of each cycle?
I have to complete this project as soon as possible. Can someone please help me? Thankyou.

Hi fedanyesha,
In the step prior to the one you mentioned, you had a built a second table that list the beginning, the peak and the end of each cycle. The date are in "decimal date" format so you should only need to subtract the number in question to determine the time period. For example, looking at the cells in step 9c, If I were to take the end date of 1766.459 and the start date of 1755.376, the length of that solar cycle can be calculated by subtracting the two numbers. (1766.459 - 1755.376 = 11.083) The 11 is 11 years. You can then convert 0.083 to days by multiplying it by 365.25 (0.083 * 365.25 = 30.3 days) if you so desired.

I hope that helps. Good Luck and please post again if you have any other questions.
Willey

That really helps.Thankyou

Hi.I have another doubt. I found the onset and decay time of each cycle and the rise time is definitely faster than decay time , but some of the cycles( 5 out of 23)have a longer rise time compared to decay time. Does that mean the hypothesis "sunspot cycles have consistently faster rise time than decay time" not true?

Hi fedanyesha,
Great question! This is the reason why "Testing for Statistical Significance" is really important to understanding and interpreting the data. (Also, please note that the hypothesis chose the word "consistently" instead of "always." So, in short, no - I would NOT say that your data set proved that the hypothesis is incorrect.)

At any rate, once you crunch the numbers on the statistical tests as outlined in the procedure, you can say what is your "confidence level" for this hypothesis.

Good Luck!
Willey

Hi. I am here with another doubt. I know that sunspot activity rises and falls in a roughly 11 year-cycle.But I read somewhere that sunspot cycle period is 22 years and now I am confused. Can you please give me a clarification?
Thankyou

HI fedanyesha,
Just out of curiosity, where did you read that the typical sunspot cycle is 22 years? I think the author may be referring to the "solar cycle" which is usually twice the sunspot cycle.

Here's a link that describes their differences: (Bottom of page)
https://scied.ucar.edu/sunspot-cycle

Good Luck and Please post again if you have any other questions.
Willey