How Did Eratosthenes Contribute To Science

Eratosthenes was an Ancient Greek mathematician, scientist, geographer, and astronomer. He was born in Cyrene, Libya in 276 BC, and died in 194 BC in Alexandria, Egypt. He was educated in Platonic Academy, which originated as Plato's school of philosophy, founded in 385 BC in Athens. He became very intrigued in Plato's philosophical writings, and he even wrote his own book, "Platonikos", which put Plato's philosophies in a mathematical light. Eratosthenes excelled at many subjects. He wrote about geography, philosophy, mathematics, astronomy, history, and even wrote poems. He was given the nicknames "Philologos", or "lover of learning", as well as "Beta", which is the second letter of the Greek alphabet. He was often called "Beta' because although

For example, he produced a reliable and logical process to discover prime numbers, called the Sieve of Eratosthenes. What he is most famous for, however, is being able to calculate the circumference of the Earth almost exactly. Eratosthenes noticed that on the summer solstice in Syene, the sun's rays shown straight down because he saw that in a deep well, the sun's rays reached the very bottom, and did not cast a shadow on the sides. He then placed a pole in Alexandria on the summer solstice and he observed that it did cast a shadow. Knowing that the Earth was a sphere and the distance between the two cities, he could calculate the circumference of the Earth. He measured the angle of the sun's parallel rays from the vertical and figured out it was 7.2 degrees. He also knew that the Earth's circumference was made up of 360 degrees, so 7.2 degrees would be about one-fiftieth of the circumference. He paid someone to find the distance between the two cities and got 5,000 stadia (the measurement for distance used at the time) and calculated that the circumference of the Earth was 250,000 stadia, or 25,000