In Class Test #1
Paragraphs on Eratosthenes
Did you ever thought of calculating he circumference of the Earth with the use of only two
sticks, because somewhere in Egypt in the 3rd century BC, as impossible as it sounds, a man
did it. Eratosthenes, or the second best of the world as he would be called after his death, was
an historian, a geographist, a philosopher, a poet, the head of the library of Alexandria but,
moreover, he was a renowned mathematician. He wanted to properly determine the size of
the Earth but, it was unclear to him how he should proceed. However, it was while reading
a papyrus in the library that he noticed something that gave him the infamous idea that maybe
the Earth wasn’t flat after all.
And, it was in Seyene, on June 21st also known as the longest day of the year that his little
experiment took place. Firstly, he noted that as noon approached, the shadow of the stick he
had inserted in the Earth priorly grew short and was almost nonexistent. Also, he saw that the
sun directly hit the water of the well next to him and that there was no visible shadow. He then
reproduced the same experience with a same length stick, on the same day and at the same time
but in Alexandria. However, his observations were not similar as he realized that this time, the
stick indeed had a shadow. He started to wonder how could his results have turnt so different,
and ended up coming to the conclusion that the surface of the Earth was curved. Provided that
he already had the mesure of the angle of the shadow in Alexandria, he thought that
maybe having the distance between the 2 cities would help him find out the total
circumference of the Earth. He hired a man to walk the distance between Seyene and
Alexandria. With this new information, he managed to multiply the said distance which was
about 800km with the angle of the shadow that turned out to be roughly 1/50 of the Earth
surface. After this operation, Eratosthenes found a result of 40000 which was off by just a few
kilometers.