Another question he asked was “how far is the Earth from the sun?” When Eratosthenes was a little older he went to the gymnasium it was a place where they learned. Eratosthenes was a good student he worked hard and was one of the top students. He asked his teachers lots of questions but some of the questions not even his teachers could answer.

He then decided to go to Alexandria. He worked there in the library. When the previous Head Librarian died or left they chose Eratosthenes as the next Head Librarian. He looked for a scroll that had all the information about Earth in it but there wasn’t any scroll in the library. After lots of research Eratosthenes found some information and put it in the scroll but there was one more thing he needed. He needed to know the circumference of the earth.

He found out that on the 21st of June the sun would point down into a well in Syene. Shadows won’t appear in Syene but in Alexandria. He knew that if he could measure the angle of the shadows he might be able to get the Earths arc because he knew that Earth was like a sphere. On that day Eratosthenes got a long instrument that looked like a stick and he used that to measure the angle then he divided that by 360°. The angle he got was 7° approximately and if divided by 360° it would equal 50 approximately. That’s how he knew the angle.. Now he just needed to know the distance. He decided to use camels to measure the distance from Syene to Alexandria. Some say that he used the average time of caravans with camels but in the book it says he used bematists. They were people who earned their living by measuring the distance of places.

The distance he found was 5000 stades (1 stade=515ft). He multiplied that by 50 and got the circumference of the earth which was 250 000 stades. In kilometer it would be 39000 which is a very accurate result. I still am wondering how he could get so near the real result. In fact Eratosthenes was only of by 200-300km. It is amazing he got so near the real result without any modern technology. We wouldn’t last even a day without modern technology. What Eratosthenes and many other scientists did was create a base for science. It is a hard task to start something then continue doing what other people have done for us. We are the one who are continuing that work many scientists have started for us.