Home Up Site Map Light Pollution What's New? Upcoming Events

Paper Plate Education
"Serving the Universe on a Paper Plate"

Activity: Sub-Solar Cup

Sub-solar_cup_pixR.jpg (13453 bytes)

This and several other activities from the Paper Plate Astronomy videotape and DVD are now available online as 
free streaming video

analemma08656.JPG (25354 bytes)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.

Sub Solar Cup North.jpg (457887 bytes)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.  



Sub_Solar_Cup_used.jpg (21894 bytes)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.  


Sub_Solar_Cup_zoom.jpg (23832 bytes)View the location of the sun at local noon throughout the year to track the sun’s annual migration between the tropics.





Sub Cup w snow.jpg (416957 bytes) Sub Cup w snow zoom.jpg (410181 bytes) Sub Cup w snow big zoom.jpg (380384 bytes) 

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.]  


Home Activities! Site Map Light Pollution What's New? Upcoming Events
The contents of this site may be reproduced for non-profit educational purposes only.  Please cite the contributing author  in credits.  
All other uses require the express written permission of the respective contributors.

Copyright 2012 Chuck Bueter.  All rights reserved.