Eratosthenes

High school (ages 12+)
Science & Technology

Name:

Date:

Step 1 · Read the article

Open the article and read it at the level above. Then answer the questions below in your own words.

https://smallwhale.org/articles/eratosthenes

Write what each word means, using the article.

Do not copy the article. Write two things you learned, the way you would explain them to a friend.

Answers below are taken from the article’s stored facts, so they match what the student read.

1. When was Eratosthenes born?Circa 276 BC
2. Where was Eratosthenes born?Cyrene, North Africa (modern Libya)
3. What is the career?Chief Librarian at the Library of Alexandria
4. What is the estimated earth circumference?Approximately 25,000 miles (40,000 km)
5. What did Eratosthenes do to measure the Earth's size?He measured the Earth's size by comparing shadows in two cities. In Syene the sun was straight overhead, but in Alexandria a shadow appeared. Using the angle of that shadow, he calculated the Earth's circumference.
6. How did Eratosthenes find out the Earth's tilt?He calculated the Earth's axial tilt, the angle that makes the seasons. This tilt is why we have summer and winter. His calculation was very accurate for his time.

Polymath: An individual whose knowledge spans a significant number of subjects, demonstrated by the ability to excel in several of them.
Axial Tilt (Obliquity of the Ecliptic): The angle between a planet's rotational axis and its orbital plane, responsible for seasonal variations.
Sieve of Eratosthenes: An ancient algorithm for finding all prime numbers up to a specified integer by iteratively removing multiples of primes.
Scientific Chronology: The systematic study and dating of historical events based on empirical evidence and logical sequencing.