The Librarian Who Measured the Earth

The Librarian Who Measured the Earth

The Librarian Who Measured the Earth

The Librarian Who Measured the World

Children like to ask questions! A kid named Eratosthenes was very curious just like kids today. From childhood to adulthood, he kept wondering about things. One of the things he was curious about was the circumference of the earth.

The Librarian Who Measured the Earth

But, how do you measure the circumference of the earth without the use of modern technology?
Eratosthenes worked at the great library in Alexandria in ancient Egypt, becoming head librarian. With no satellites, computers, or modern transportation, he figured out a method for measuring the earth’s circumference that was accurate to within 200 miles, as measured today. Wow!!

His story is told in the book The Librarian Who Measured the Earth written by Kathryn Laskey and illustrated by Kevin Hawkes. It is a picture book with beautiful illustrations that help to tell the story. It inspires many ideas for science and math connections in grades 3 – 5.

The Librarian Who Measured the Earth
One way to use this book is as an introduction to the scientific method. The scientific method includes asking questions, researching current literature, formulating a hypothesis, testing and experimenting, recording data, presenting the results. Eratosthenes does all of these in the book. If your school has a science fair, try using this book as a preparation to the event. Students can think through their own questions, do some research – a fantastic way to work with the school librarian – and develop their projects from there.
One way to approach the research element of the book is through the Big 6 Research method. This approach lays out 6 basic steps for good research. It makes the research process more clear for most students.

Math, Geography and Astronomy

Students will love learning more about astronomy since Eratosthenes uses the summer solstice as part of his calculations. Integrate math into your studies since shapes, angles, distances, and most certainly circumferences are all part of the calculations involved Eratosthenes work. Even the social sciences are represented. Geography using map skills and history could be brought in to the discussion. This book is great inspiration for a math day complete with costumes!

The book features many content words that the author explains. Some of these are: styluses, geography, chronology, constellations, ecstatic, promenades, museum, papyrus, flatterer, axis, sphere, circumference, angle, bematist, stade.
Besides working with the librarian, if your school uses different teachers for different subjects in the upper grades, you can get the rest of the team involved in the study.

Resource Links: A bibliography is included in the book. If you would like to order this book for yourself. I have provided a link for you!

Some video resources are:  The video Eratosthenes gives a great summary about Eartosthenes about as a scientist! Including “The Sieve of Eartosthenes” which is a great way to find prime numbers on the 100s chart.  Your students will enjoy this activity. Print your own chart by clicking on this link: 100s Chart SIEVE of Eratosthenes


Sarah and Betsy

Written along with Betsy Ruffin. Besty is a retired teacher librarian, current technologist writer, and lifelong reader book-lover.


Sarah Winchell is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to

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Hello and welcome to Science is for Kids! I’m Sarah, the author, and I’m glad you dropped by to visit my site. I love providing teaching ideas for elementary science teachers, and here, you’ll find my favorite lessons and resources to make learning science fun for kids. You can visit my About Me page to learn more.


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