Re: How can I demonstrate sun spots affect the radio transmissions on earth?

Hello, Rebecca!

Sunspots themselves are not directly the cause of radio interruption. Solar 
activity (of which sunspots are one manifestation) is, by sending large 
pulses of charged particles (these are called coronal mass ejections, or 
CME) outward.  The charged particles "bang into" the Earth's magnetic
field and disturb it. This in turn causes changes in the ionosphere (a zone
high in the atmosphere). Since many radio waves reflect off the ionosphere,
the reception of these signals is then changed (usually for the worse) and
other things also happen: auroras, blackouts caused by large surges of 
energy into power systems, etc.

For you to demonstrate the actual cause and effect is quite difficult, as it 
will require that you have some method to track CME--something that is going 
to take equipment you are not likely to have. But there are some alter-
natives that will allow you, over time, to demonstrate the correlation
between solar activity and radio transmissions.

One way is to have a telescope equipped with a solar filter and observe the 
numbers and sizes of sunspots directly. You *MUST* have help on this, to
make absolutely certain that the equipment is correctly set up. Improperly 
done direct telescopic observation of the sun can cause severe and 
irreversible eye damage. Visual observation of sunspots is also subject to 
interference from plain old clouds. You will also need a radio receiver 
(short wave is probably best, or AM at night) that can pull in distant 
stations.  Start observing the sunspots, and note which stations you can and 
can not receive each day. The radio reception check should be done at a 
specific time (relative to sunrise and sunset) each day...especially with AM 
radio...as there are changes in the ionosphere from night to day even 
without any major changes to solar activity.  

A second alternative, which avoids the use of a telescope,  is to build or 
buy a radio receiver that will pick up the 10.7cm wavelength emissions from 
the Sun. This signal has been measured for some 50 years and is a good 
measure of solar activity. There is a statistical correlation between the 
10.7cm signal strength and sunspot number:

          N  =  (1.14 * Flux) -73.21  where

                                           N is the sunspot number
                                           Flux is the 10.7cm flux 
                                              expressed in "solar flux 
                                              units" of
                                                1E-22 W/(m^2)(Hz)

You will still need the short wave and/or AM radio receiver to check which
stations you can receive.

The issue of solar activity has significant implications for geostationary
communications satellites (which are well above the atmosphere, and thus 
relatively unprotected from the surges of charged solar particles) , and you 
will find  that there are already regular "solar weather predictions" made.  
NASA does this, and I am sure that other organizations do as well.

Lastly, read the article (pp. 94-98) on solar activity by Ken Tapping in 
"The Observers' Handbook, 2002", published by the Royal Astronomical Society 
of Canada. It is not a heavily technical presentation, but it does contain 
concepts likely to be new to you. Your science teacher should be able to 
help you understand it.