Stimulating Understanding of Computational science through Collaboration, Exploration, Experiment, and Discovery for students with Hearing Impairments
a collaboration of the Shodor Education Foundation, Inc., Eastern North Carolina School for the Deaf, Barton College, the National Technical Institute for the Deaf, and Interpreters, Inc.

For Teachers!

Predicting Lunar Eclipses Extension

Extension

After reading the theory behind the Saros, the students will know that 223 Synodic months, or 29.530589 days times
223, is 6585.321 days. 242 Draconic months, or 27.212220 days times 242, is 6585.357 days. These cycles are
almost the same: 6585.321 days and 6585.357 days. Have them use a spreadsheet to find how many minutes they
differ by. 

Are there any other cycles that can be used to predict eclipses? The students can create a spreadsheet that produces
multiples of synodic and draconic months. Then they look at the products for pairs that are close. Several pairs are
on the same day but the Saros is an order of magnitude better than its nearest rival. Some of these other series will
work for a handful of eclipses but none come close to the Saros, which predicts between 71 and 73 eclipses. 

Moon phases for the twentieth century.

http://sunearth.gsfc.nasa.gov/eclipse/phase/phases.-1999--1900.html

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This project is supported, in part, by the National Science Foundation Opinions expressed are those of the authors and not necessarily those of the National Science Foundation.