It is possible to benefit from the Sunwheel with a simple visit to the stone circle, and see that there is an enormous variation in the Sun's location along the horizon during the course of the year. With repeated visits to the Sunwheel to see the Sun rise or set, one can observe how the Sun's position changes noticeably along the horizon over the course of the seasons. Better still, one can visit the Sunwheel at sunrise or sunset on the Solstices and Equinoxes to be fully present as each season begins, and to see the Sun line up with the stones in the Sunwheel. For more in-depth explorations, the projects which can be done using the Sunwheel are many and varied, including projects to be done during the day, at night, at sunrise, or at sunset.
One project involves monitoring the rate at which the Sun's location along the horizon changes during the course of the year. These observations are most easily done by several students, with one student sighting from the center of the Sunwheel, and another student standing at the radius of the Sunwheel, in line with the rising or setting Sun. Students should keep a record of where they stand on what days to be in line with the Sun, and they will use these observations to determine the rate at which the Sun's rising and setting locations moves along the horizon. These observations make it possible to determine the times when the Sun's position along the horizon changes the fastest or the slowest. The students who do this project should make one or more weekly visits to the Sunwheel at either sunrise or sunset.
The setting Sun appears over a student's head in November.
A second project focuses on observing the Moon rise and set from the Sunwheel to explore the differences between the lunar and solar motion. These observations demonstrate that the Moon takes only one cycle of phases to span the full range of rising and setting positions along the horizon that the Sun experiences in 1 year. They also demonstrate the effects of the tilt of the Moon's orbit relative to the ecliptic, since the Moon can also be as much as 5° north of the Sun's summer solstice position or south of the Sun's winter solstice position at its extremes. The students who do this project should make 2 visits to the Sunwheel per week for 1-2 months.
A third project is one which will be done at night, observing the stars rise and set, and observing the position of the north star, Polaris. These observations indicate that the stars rise and set at fixed locations along the horizon, unlike the Sun, Moon, and planets. After finding Polaris, students should observe the location of this star relative to the North stone at the Sunwheel. Students should visit the Sunwheel at the same time every week for several months, and verify that Polaris is always close to the same place in the sky. Also, students will discover that the stars are in slightly different positions from week to week. Through selecting a bright star to watch rising or setting while at the Sunwheel, observers will determine the location along the horizon toward which this star rises or sets, verifying over the course of several months that the rising and setting locations of the stars along the horizon do not change.
The gibbous Moon rises on the autumnal equinox.
DAYTIME SHADOW PROJECTS
Finally, there are daytime projects which can be done at the Sunwheel involving observations of the lengths of shadows of the standing stones. By visiting the Sunwheel at around noon throughout the year, it will be possible to determine the lengths of shadows and the changes in the lengths of the shadows of the standing stones. This will help teach students about the changing altitude of the Sun in the sky throughout the seasons. Measuring the lengths of the shadows close to the solstices will indicate the maximum and minimum lengths of the shadows.
With help from several graduate students in Education (Melissa Goldman and
Bill Randolph), we have created several lessons on topics which relate to the Sunwheel
for teachers of middle school classes and up. Two lessons are now
available, as indicated below. The lessons are on topics including:
(1) FINDING THE CARDINAL DIRECTIONS USING THE SUN
(2) MEASURING THE TILT OF THE EARTH'S AXIS
(3) CHARTING THE SUNRISE & SUNSET THROUGHOUT THE YEAR -- in preparation
(4) CHARTING THE MOON THROUGHOUT THE YEAR -- in preparation
A project conceived by Professor Judith S. Young
Astronomy, University of Massachusetts, Amherst
e-mail: send to Judith Young at