Eratosthenes Calculates the Circumference of the World
Grades: 3 - 8

Video Description: Learn how Eratosthenes, way back in ancient times, successfully calculated an accurate measurement of Earth’s circumference.

Type of Video: Topical*
Unique Video ID: Maps-9**

Quick Ideas for Using the Video:

  • Before viewing the video, check for student understanding about the word “circumference” and how that word applies to the Earth.
  • As students view the video, have them create a list of the “educated guesses” that Eratosthenes made and how he sought to validate what he believed to be true. Discuss the examples after viewing the video.


*Topical videos are filmed on location in the classroom/workspace/laboratory, in studio, or a combination of both to explain and/or demonstrate specific concepts, events, topics, or processes.

**The unique Video ID can be used to quickly locate a single video in the ET collection. This search function is designed to let teachers assign students to watch a specific video and have only that video appear as a search result. Just click on Search and choose “By Video ID.” Then type in the Video ID as it appears above. Be sure to include the dash.