The Librarian Who Measured The Earth
By Kathryn Lasky
Illustrated By Kevin Hawkes
Published By Little, Brown And Company
Ages: 9 - 12
Say you want to find the circumference of the Earth, how would you go about it?
The object to be measured is not a perfect sphere. But let us approximate it to be a sphere to keep things simple. The formula to be used is 2πr, provided, we have a value for r.
Let us not forget that you are in the 21st century, where, with the click of the key board, you can get the radius range of the Earth. You have grown up with the image and terminology "sphere that is flattened along the axis". This has been reinforced by satellite imaging. Also π = 22*7 has been given away to you for free, chiseled in to your brain by your 5th grade math teacher!
Suppose you lived in 3rd century BC, how would you calculate the circumference of the Earth? First, if you are living in 3rd century ancient Greece and you are thinking about measuring the Earth, then you are of a different cut! Second, you will be going by a whole lot of assumptions, no satellite imaging and GPS to help you there, sorry! Third, you will be looking through truck loads of papyrus scrolls to back up the assumptions you are making!
These were the thoughts that ran through my mind as I read the book. There definitely was a sense of wonder as I read the blurb. What little information that was available on Amazon's look inside did not satiate me and I did not rest till I bought my own copy of the book.
The Librarian Who Measured The Earth is the picture biography of Eratosthenes, a scholar who lived in 3rd century BC. He was a mathematician, geographer, music theorist and the chief librarian of the Great Library of Alexandria. The book takes us through the life of Eratosthenes, but of all his achievements it focuses on how he measured the Earth. The process he used is well described in detail by Kathryn Lasky. The illustrations that go with it are not the typical text book illustrations.
My only comment would be, to instill the sense of wonder, Lasky talks about about ancient Greece, the different radical though processes brewing, the Great Library of Alexandria, which dilutes the book.
And to actually know how Eratosthenes pulled it off(to this date his measurement has been accurate), you could google it. But google does not come with the beautiful illustrations of Kevin Hawkes. So visit your local library and if your library does not have a copy, recommend a buy.