We love TED, it shares new ideas based on the activity of renown scientists, economists, artists, etc… It makes knowledge more accessible so we are proud to everyday share with you a TED video. Hope you enjoy it!
I decided to put here a TED-Ed video, I know that it isn’t a regular TED, however this video is special and takes only 7 min.!
In our academic life, as well as in our daily life, we’ve always found things that we couldn’t understand. And probably in most of the cases we entrust in others to decipher those things because we are not able to do it… In this brilliant talk Adam Savage, a former co-host in Discovery Channel series “MythBusters” and “Unchained Reaction”, attempts to debunk this assertion. From Eratosthenes to Richard Feynman, he presents us knowledge that started from simple ideas that everyone can discover from their experience.
First things first, let’s know who was Eratosthenes, then we will proceed for the answer to this task.
Eratosthenes of Cyrene was a Greek mathematician, geographer and astronomer (he yearned to understand the complexities of the entire world so he was devoted to many areas). He lived between 276 BC – 194 BC and during that time he changed the way we view the world. He created geography and made some progress in science especially mathematics (he created a tool for discovering prime numbers). He is now known for being the first person to measure the Earth’s circumference. 
If you didn’t understand it completely, here is better explained. (Any doubt or suggestion be sure to leave it in the comment section)
References and further reading.
 – Eratosthenes – Wikipedia
 – Eratosthenes – The MacTutor History of Mathematics archive
 – Eratosthenes – Encyclopaedia Britannica
 – (Project for school students) http://www.bibalex.org/psc/en/GetInvolved/Eratosthenes.aspx