Kickoff Message, September, 2002
Prelude Why I Developed this Website by Ihor Charischak
The Story The Librarian who Measured the Earth - Details of how Eratosthenes (275-194 BC) the chief librarian of the finest library of his time made his remarkable measurement.
Some ideas for teaching this unit Strategies for teaching and learning this "unit".
Doing the measurements Helpful suggestions for doing the project.
The angle measurement you need is the one formed by the meter stick and the sun's rays (the acute angle opposite the base angle of the triangle formed). In the photo its the angle that is covered by the protractor.
Using Trigonometry An introduction to the ideas used by Ken in his spreadsheet explanation below.
Using Spreadsheets Ken Cole's explanation from the 1997 project.
Some Useful Tools
A Java Sketchpad model which lets you explore the angles formed by the sun's rays at Alexandria and Syene. (Being revised)
A Java Sketchpad model which lets you explore when there are shadows at both locations. (Being revised)
Finding your distance between sites
You don't need to necessarily partner with someone on or near your longitudinal (north-south) line. But you do need to find the north-south (or perpendicular) distance between your latitude and your partner's latitude. (You can also partner with the equator! See how Ken Cole did it.)
Tools for finding Local Noon