
Me and My Human,
2004
Skaters at the Lasker Rink in Central Park are dwarfed by their
shadows, at least in this aerial view, Feb. 22, 2004.
Click on image for a larger view.
Sing a Song for
Longitude And Latitude!
See Space Song
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Resources
that
discuss Eratosthenes and his Measurement
- Following in the Footsteps of
Eratosthenes: Measuring the Circumference of the Earth http://www.mapmonde.org/eratos/
Very
impressive. In several different languages no less.
Books
Here
are some titles you will find in your favorite book store, library or
on-line.
- Ferguson, Kitty. Measuring the Universe.
- Lasky, Kathryn. The Librarian who Measured the Earth. A must buy!

- Diggens, Julia. String, Straight Edge, and Shadow (p.
149-154)
- Sagan, Carl. Cosmos. The
book and video from a PBS
series
of the same
name.
- Coggins, Jack. By Star and Compass. The Story of Navigation
(p. 64-69) Good
explanation and diagrams.
- Moore, P. and Brinton, H. Exploring Maps. p. 13-15
- Gullberg, Jan. Mathematics: From the Birth of Numbers. p.
467 Did
Eratosthenes really get the measurements right? According to Gullberg,
historians have done some fudging to make Eratosthenes look good. Since
his method was correct, why not give him the benefit of a doubt that he
used the right length for his unit of measure - the stadion? Apparently
there were at least seven different lengths for a stadion at that time.
Shadows
I found these books in the children's section
of my
local library. If you find any good books, let me know and I'll add
them
to this list.
- Adler, Irving. Shadows
- Gardner, Robert & Webster, David. Shadow Science
(Doubleday, 1976). The
authors take a fresh look and gives us clues about the world around us.
Titles of chapters include: Telling Time with Shadows, Finding North
with
Shadows, and Night is just a big Shadow. Contains a lot of puzzle
pictures. Great book.
- Severn, Bill. You and Your Shadow.
Articles
- Charischak, Ihor. In the Spirit of Eratosthenes: Measuring
the
Circumference
of the Earth. Learning &
Leading
with Technology, V. 25, N. 6 (ISTE, March, 1998)
- Charischak, Ihor. Bringing
the Vision of 21st Century Collaborative Projects Into Today's
Mathematics
Classrooms. Paper presented at the NCTM's
Electronic
Format's Group Conference, Reston, VA, June, 1998
Relevant
Websites
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Other
Eratosthenes Measurement Projects
Participants
Websites
Read
about the Noon Day Project in the News
Video
- Cosmos #1: The Shores of the Cosmic Ocean (1980) Carl Sagan
Productions/PBS,
1/2" video Color 1 cass., 60 min. Explores the
universe
from clusters of galaxies to the Milky Way and earth. Discusses early
scientific
discoveries concerning measurement of the earth's circumference and its
spherical nature. Journeys through time from the Big Bang to the
present. Included in this video is a wonderful presentationn of Carl
telling the Eratosthenes measurement story. See link below (with French
subtitles.)
- http://video.google.com/googleplayer.swf?docId=-3973356878310464582&hl=en%22flashvars=%22
Notes
Aristotle believed the earth was round, but he
low-balled how
round it was. King Ptolemy of Egypt offered an estimate of 18,000 miles
which Columbus used to his advantage in negotiating for his trip. (From
a PBS interview with author of Don't Know Much About the Cosmos.)
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Somewhere on or very near
the Tropic of Cancer or the Tropic
of Capricorn.
(Why?)
Congratulations to the students of Mr.
Langstaff at
Hendrix Junior High in Chandler, AZ for being the first to come up with
that.
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Additional
websites and other strange phenomena
If I
dig a very deep hole, where I go to stop?
Was your mother right when she
said that if you dug a hole through the
earth to the other side you would wind up in China? Assuming you are in
New York City, how close to China would you end up? Not sure? Try this completely "stupid" use
of Google Maps.
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