Background:
Vocabulary

Sunspot Solar CycleSolar Irradiance Black body
Solar Flare


Our sun is a variable star. Electromagnetic radiation emissions from the sun fluctuate over time. Fluctuations in solar radiation vary according to wavelength and can be linked to solar cycles. In this activity students will investigate solar activity cycles and fluctuations in solar radiation.
For additional background information see Solar Cycles Brief


Procedure:
GET & PRINT WORKSHEET

Step 1: Examine the historic sunspot data below. The two graph show the number of sunspots recorded from 1976 to the present. Dates of observation are given by the last two digits in
the year and the number of the month. 7606 refers to an observation made during June of 1976. The jagged line shows the actual sunspot number. The smooth line is the “smoothed” sunspot number. Click here to go to solar cycle graphs.
Sunspot / Solar Cycle Graphs
As you examine the graphs answer the questions on your worksheet.












Step 2: Satellite solar irradiance data is available from 1978 - the present. "Irradiance" is the amount of electromagnetic energy incident on a surface per unit time per unit area. The units for irradiance on the graph are Watts / meter2/sec..These measurements include the entire solar spectrum. The solar irradiance recorded from several NASA satellites is shown below. Data from each satellite is shown in a different color. Examine the graph below and answer the questions on your worksheet.







Step 3: SOLAR ACTIVITY CYCLE AND SOLAR INSOLATION CYCLES
Compare the Solar Activity Cycles to the Solar Irradiance Cycles. Answer the questions
on your worksheet and define the relationship between the two cycles.




Step 4: SOLAR FLARES
Visit the NASA site below and then define a solar flare on your worksheet.
SOLAR FLARE DEFINITION

Examine the solar flare classification table to identify the relationship between solar flares
and the solar activity cycle.
SOLAR FLARE EVENT CLASSIFICATION


Step 5: SOLAR FLARES AND VARIATIONS IN SHORT WAVELENGTH EMISSIONS
As mentioned in the solar radiance brief, the sun is not a perfect black body. The graph below illustrates the difference between Solar irradiation outside the earths’ atmosphere & at the earths’ surface and the irradiance for a black body at the same temperature as the sun. Examine the graph below and answer the questions on your worksheet.












Step #6: WHY DO I CARE ABOUT VARIATIONS IN SOLAR IRRADIANCE A SPECIFIC

WAVELENGTHS???????


Now that you have identified the wavelengths at which solar irradiance varies the most, you are ready to take a summary look at why these variations are important to the earth system. Visit the sites below and answer the questions on the worksheet.

IRRADIANCE AND OZONE
Ozone Formation Basics
IRRADIANCE AND RADIO COMMUNICATIONS
Short-Wave Fadeouts and Solar Flares
IRRADIANCE AND SATELLITE DRAG
First Warning-The Arrival of X-Rays


****TEACHER NOTE****

Variations in irradiance is only part of the study of solar activity cycles. Variations in charged particle emissions are also associated with solar activity cycles. The study of these emissions can be linked to: solar wind studies, geomagnetic field disturbances, satellite operation, and aurora intensity. There are student activities on these topics on the NASA Goddard Space Flight Center Educational Mall.






 

Coding:

Maryland Core Learning Goals (Science):
National Standards (Science): A:3 D:1 E:2
National Standards (Geography): 1:1 7:1,2,3
National Standards (Mathematics): 1:2,4 5:1

Investigation Discussion and Questions

All investigation calculations and questions appear on the student worksheet. It is suggested that the investigator print a copy of the worksheet and complete it as they go through the activity.




Credits:
Gregg A. Stickler Lee Kyle
NASA Teacher Ambassador NASA Goddard Space Flight Center
GESSEP Program Distributive Active Archive Center
Greenbelt MD