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Paper Plate Education
"Serving the Universe on a Paper
Plate"
Activity: Sub-Solar Cup
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This and several other activities from
the Paper Plate Astronomy videotape and DVD are now available
online as
free streaming video! |
 Throughout the year, this simple device will indicate where
on the Earth the sun is currently overhead.
See the Analemma activity to plot a figure-8 analemma
(right) on a globe using the Sub-Solar Cup.
Drill a small hole out of the bottom of a dark plastic cup. On the top of the cup secure two pieces of thread to
make a set of cross hairs. Cut out
a viewing window on the side of the cup.
 Secure the globe on its side so that a figure standing at
the observer’s location is upright on the globe. That is, a tangent at the observer’s location is parallel to the
ground. Align the figure’s line of
longitude on the globe with your north-south meridian.
 Position the cup upside
down on the globe so that sunlight goes through the small hole and is centered
over the cross hairs. That location is the current sub-solar point.
 View the
location of the sun at local noon throughout the year to track the sun’s
annual migration between the tropics.
This activity,
contributed
with original reference by
Gary Tomlinson, is an adaptation of an activity written by Robert
Mitchell. See The Physics Teacher, May 1991, pp. 318-319.
GLPA Proceedings, 1999, pp. 36-36.
[Note: This activity is included in the
Paper
Plate Astronomy video/DVD/streaming video.]
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