Eratosthenes was a person filled with wonder and curiosity. His biggest question was how to measure the earth. Knowing he couldn't walk around and measure, he decided that he was going to figure out how to measure the earth in one spot. This chief librarian of Alexandria's great library devised a way to calculate how big the earth is and his calculation was only 200 miles off from today's measurements. This story is an awesome look into the past with math that we still use today. ( )

This amazing nonfiction children’s book tells the brief life story of librarian Eratosthenes and his discovery on the Earth’s circumference. Taken place in ancient Greek history, Eratosthenes is described to be a mind full of curiosity and wonder towards Earth as he makes further discoveries correlated from science and math. This book is such a wonderful and creative book that can be used with young readers to introduce introductory topics among math and science content areas. In math, this book can be used within an introductory lesson of circumference as this book goes into depth creatively about what circumference truly is. This book can also be used among science content lessons to go over the scientific method and the importance of formulating questions that can be tested using a scientifical experiment the way Eratosthenes tested his hypothesis on the circumference of the Earth. Additionally, author Kathryn Lasky provides fun facts throughout the book that can keep the reader engaged and amazed. I also like how this book correlated towards ancient Greek and Egyptian culture as it can be a great world history read when covering ancient history. ( )

Eratosthenes' determination and wonder-filled questions lead him to be able to measure the circumference of the Earth. I learned a lot from this book! It is filled with historical facts and small details about the time period that I had not known before. Towards the end, the math gets a little overbearing but I think that would make this great for older students who are using this as an introduction to a math or geography lesson. The book gives a full overview of Eratosthenes' life and was an inspiring read. ( )

Somewhat over inspirational biography of Eratosthenes. There are really nice illustrations of Eratosthenes technique for estimating the circumference of the earth, however. Also a new word, "betamist". A betamist is an especially trained walker, whose paces can be used to calculate distances. Alexander of Macedon kept a few, so he could map out the empire he conquered with reasonable accuracy. ( )

Excellent children’s nonfiction book. The writing is creative and reads like a story. The details in both the text and images are amazingly accurate and make learning about Eratosthenes enjoyable. The book would be a great introduction to math concepts of measurement and geometry. The book could also be used to learn about ancient Greek and Egyptian culture. ( )