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The Planet Earth. What is the SIZE of the Earth?. Can you measure the SIZE of the Earth from your observation point?. 200 BC. ERATOSTHENES Measured the distance around the earth without leaving E gypt.
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Can you measure the SIZE of the Earth from your observation point?
200 BC ERATOSTHENES • Measured the distance around the earth without leaving Egypt. • Assumed the earth is perfectly round and represented it in his drawings with a circle.
Eratosthenes’ Way • Measured the distance between Syene (present day Aswan) and Alexandria 500 mi ≈ 800 km
Summer Solstice • June 21st • Longest day of the year
Eratosthenes’ Calculation Circumference of the Earth:25000 mi Find the diameter and radius of the Earth
Measure of the Earth Circumference ≈ 24 900 mi ≈ 40003.60 km Diameter ≈ 12 740 km Radius≈ 6370 km Note: These are only approximates since the earth is not perfectly round
7 926 mi ≈ 12 756 km 7 900 mi ≈ 12 714 km
THINGS TO BRING: • RULER • PROTRACTOR • DRAWING COMPASS