Visibility of eTwinning Projects Group July 2025 Newsletter
Students need to understand that in order to make the calculation, we must define the angular distance between the two locations.
• Round Earth:
Hypothesis or preliminary explanation
• Based on the ideas above, can we come up with a plan to measure the circumference of the Earth?
• Let’ s see how Eratosthenes did it! Eratosthenes’ experiment was based on a chance observation: in Syene, the sun was reflected at noon on the surface of a deep well, while at the same time, an obelisk in Alexandria cast a small shadow.
• Since Eratosthenes knew that the Earth was a sphere, why was he puzzled by this observation?
• If the Earth is a sphere, this observation could be explained by the fact that the sun’ s rays reaching Earth are parallel.
• Ask the students to write down their ideas.
• Let’ s build some models to see how we can make the same observation.
The shape of the earth The two models are presented:
• Flat Earth:
Which one do you think is correct? After observing the models, go back to the question and check your answer. Is your answer correct, or would you like to change it?
Planning the investigation Let’ s see what are the essential factors for our investigation.
To carry out the experiment, we need to consider the timing.
Take into account the local time of the partner school and perform the experiment at the same time.
Take into account the local time of the partner school and perform the experiment when the sun is in the same position in the sky for both schools.
Use sticks of the same length.
The same number of students should perform the experiment.
( The horizon is straight.)
In order to measure the distance between the two schools, we will need to:
• measure the direct( straight-line) distance between the two schools.
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