Eratosthenes Experiment – September 24, 2018

Etching of Eratosthenes. Credit: Public Domain

Teachers! Take note! Have your students take part in the Eratosthenes Experiment – Sept. 24, 2018!

Eratosthenes was a mathematician, geographer, poet, astronomer, and music theorist who lived in ancient Greece. In 240 B.C. Eratosthenes made the first good measurement of the size of Earth’s circumference.

You can join with classrooms around the world and repeat his experiment with your students!

The Experiment:

A student performing the Eratosthenes experiment. Credit: http://eratosthenes.ea.gr/

Ask your students to calculate the circumference of the Earth and submit your data to the experiment’s website.

1. Find the time of your local noon at your location. Please use the web-based NOAA Solar Calculator or Solar Calculator or the Stellarium software (A short guide for using Stellarium to calculate your local noon at your location can be found here in English and in Italian).
2. Take a one-meter stick (H= 1 meter, see figure below) and place it vertically to the ground. Ask your students to measure the length of the stick to make sure it is one meter long. At the time scheduled to conduct the experiment, ask your students to measure the length of the stick’s shadow (length S in the figure below). Repeat the measurement 5 times and write their values down in the form found in the Submit Your Data area in the website.
3. Provide to the students the value for length (L) of the third side of the triangle in the picture below or ask them to calculate it themselves by using the Pythagorean Theorem (L²=S²+H²). Write the value in your notebook.
4. Calculate the distance using Google Maps between your school and the school you have matched up with. (A short guide on how to perform the measurement using Google Earth can be found here in English and in Italian. An alternative method using the interactive mapmaker can be found here). Provide the students with the value of this distance between the two schools. Write the value in your notebook.
5. In case of a cloudy weather please follow the instructions here on how to get a measurement of the Earth’s circumference

Lesson Plans: http://eratosthenes.ea.gr/content/lesson-plans

September 2018 Photo Contest

Take a photo of the experiment or the work behind it or a creative snapshot of those involved in the experiment, submit it to the Eratosthenes Photo Competition and win a scholarship to attend European Science Education Academy (ESEA) Summer School 2019 in Greece. Teachers from all over the world, that register on our site, are eligible to take part in the photo contest. The deadline for submitting your photo is the 10th of October 2018. Furthermore the winning Teacher in collaboration with his/her students will have the chance to submit a manuscript on the new peer reviewed Scientific Journal ‘ Open Schools Journal for Open Science’. The journal hosts original articles aimed at and created by students of ages 10-18 prepared in collaboration with their Teachers. More info on https://ejournals.epublishing.ekt.gr/index.php/openschoolsjournal/about.

September 2018 Photo Contest: http://eratosthenes.ea.gr/content/photo-contest-september-2018

The Eratosthenes Experiment is organized with the collaboration of the Hellenic Mathematical Society, the participation of the UNESCO regional bureau for Science and Culture in Europe, Venice (Italy) and is approved by the Department of Education in Greece.

Eratosthenes has a crater named after him on the Moon:

Eratosthenes crater on the Moon. Mosaic of photos by Lunar Reconnaissance Orbiter, made with Wide Angle Camera. Size of the image is 80×80 km, north is up. Credit: NASA/JPL-Caltech