Eratosthenes measured the circumference of the earth by measuring the distance between two cities. Then he measured the angle of sunlight relative to the vertical on the summer solstice. The sun was overhead in Alexandria but seven degrees away from the vertical in Syene.
How did Eratosthenes estimate the size of the earth in 240 BC?
How did Eratosthenes estimate the size of the earth in 240 bc? By comparing whether sun light could reach water down in water wells in two cities at different latitudes and using simple trigonometry.
How did measure the size of the earth?
On the day the Sun shone on the bottom of the wells in Syene, Eratosthenes measured the Sun’s position in the sky over Alexandria. It was seven degrees away from the zenith, meaning Syene must be seven degrees away from Alexandria as measured on the circle that is Earth’s circumference.
What is the circumference of Earth hint apply the technique used by Eratosthenes to measure Earth’s circumference?
Eratosthenes hired a man to pace the distance between the two cities and learned they were 5,000 stadia apart, which is about 800 kilometers. He could then use simple proportions to find the Earth’s circumference — 7.2 degrees is 1/50 of 360 degrees, so 800 times 50 equals 40,000 kilometers.
What is the circumference of the earth using Eratosthenes method quizlet?
The lad measured the circumference of the earth. He was told that at a certain time, the sun was going to line up perfectly perpendicular to a well that was located in Syene. So Eratosthenes measured the distance from Syene to his place in Alexandria. He measured this distance to be 500miles.
How did Eratosthenes estimate the size of Earth in 2040 BC?
Eratosthenes had someone measure the distance between Alexandria and Syene. He used that distance, what he knew about the Sun’s angles, and a bit of geometry to figure out the size of the Earth.
What was Eratosthenes experiment?
Eratosthenes analyzed the observations with the assumption that the earth is a sphere and the sun is very far away. The geometry of the situation is sketched at the right. He concluded that the circumference of the earth was about 50 times greater than the distance from Alexandria to Aswan.
What did Eratosthenes do?
Eratosthenes, in full Eratosthenes of Cyrene, (born c. 276 bce, Cyrene, Libya—died c. 194 bce, Alexandria, Egypt), Greek scientific writer, astronomer, and poet, who made the first measurement of the size of Earth for which any details are known.
How did Eratosthenes measure the distance to the sun?
Using a gnomon, he measured the sun’s angle of elevation at noon on the solstice in his hometown of Alexandria, and found it to be 1/50th of a circle (7°12′) south of the zenith.
Which aided Eratosthenes measured the circumference of the Earth?
Eratosthenes knew that in the city of Syene, Egypt, the sun’s rays fall vertically, casting no shadow. So he measured the angle of the shadow in Alexandria and using the 500 mile distance between the two cities, he calculated the circumference of the earth.
When did Eratosthenes calculate the circumference of the Earth?
In the third century BCE , Eratosthenes, a Greek librarian in Alexandria , Egypt , determined the earth’s circumference to be 40,250 to 45,900 kilometers (25,000 to 28,500 miles) by comparing the Sun’s relative position at two different locations on the earth’s surface.
What is it called when a planet temporarily moves westward in the sky?
When a planet temporarily moves westward in the sky over the course of several weeks or months (instead of eastward, as it typically does), we call it. retrograde motion. Every celestial object appears to go around the Earth once a day.
Which of the following examples describes a situation where a car is experiencing a net force?
Which of the following examples describes a situation where a car is experiencing a net force? The car is making a gradual turn.
Why did the ancients believe that celestial objects had some influence over their lives?
Why did the ancients believe that celestial objects had some influence over their lives? They realized that seasonal changes were related to the positions of celestial bodies, so they figured that these objects could control other aspects of their lives.
