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Antarctica · 05-15-2010, 06:15 PM

Quote:

Originally Posted by BluePhyre

Phyre listened to the correct answers and sighed, raising her hand to try again. "If any calculations had gone wrong, the entire measurement could be off," she said shakily. "Furthermore, if he had used a different amount as a stadia, then he would have been wrong, and yet credited to this day to be extremely accurate, as accurate as one could be with the technology available at the time. Because of the differing measurement systems and opinions within the same measuring system, his method, while perfected by himself, would not be able to be used by many others of his time. While it's not a limitation on Eratosthenes himself, it would effect his method."

"I agree, but we are the ones who don't know how much a stadium was. Eratosthenes was certainly aware of the length of one, but that knowledge has been lost. But if we take his value of 5000 stadia for the distance between Alexandria and Syene, then we can get an approximation of how long he and his contemporaries thought a stadium was."

SPOILER!!: Quotes

Quote:

Originally Posted by feltbeatslover22

Trixie raised her hand. "Do you mean how he can't be exactly right?" she asked. "Well for a start Syene isn't exactly on the Tropic of Cancer, but slightly North, and he used this in order to make his measurements. And as I mentioned just a minute ago, Alexandria isn't exactly south of Syene. The last is that the sun appears as a disk located at a finite distance from the earth instead of as a point source of light at an infinite distance" she siad sounding like a ravenclaw. Woah. "So therefore the distances weren't exactly reliable" she smiled. "But giving him credit, his measurements were extremely close to the actual measurements. Which as you said was pretty impressive for a guy of his era" she giggled.

Quote:

Originally Posted by xiiWishiWasYours

"Some limitations were that overland distances weren't reliable because of the travel on the Nile river, they were also not completely accurate because of the locations were not exact as well, but an estimate," Selena tried.

Quote:

Originally Posted by Harry174

Simon put up his hand. "the accuracy of his calculation was limited. The accuracy of Eratosthenes' measurement would have been reduced by the fact that Syene is slightly north of the Tropic of Cancer, is not directly south of Alexandria, and the sun appears as a disk located at a finite distance from the earth instead of as a point source of light at an infinite distance. " He said before continuing. "The greatest limitation to Eratosthenes' method was that, in antiquity, overland distance measurements were not reliable." Simon hoped that he was right but wasn't sure.

Quote:

Originally Posted by DanialRadFAN01

Chris raised his hand to answer the Astonomu Professor's question, "Professor, a limitation of his method was that the angles like that can only be measure at about a quater of a degree and the distances that he covered on land were not reliable enough to make the equation work out correctly." the Gryffindor stated. It was too bad really, the man was a good thinker for the time at least.

Quote:

Originally Posted by Zecaar

Santi was surprised at how he actually liked it when a professor agreed with him. He'd never been one for participation before. But deciding to give it another go, he raised his hand. "That it can't be used for much else," he suggested. "Not to mention its lack of accuracy. Any error would multiply by fifty times due to scaling up." Santi sat back again. Okay, that was it. He was done talking... perhaps. He had no idea why, but this astronomy discussion made him want to input... why would that be?

Quote:

Originally Posted by Poisonedbyyou

Limitations, now. Abby thought for a moment. "Of course, there's the obvious one," she said. "By step counting, the distance he found between Syene and Alexandria couldn't be perfectly accurate." Now for the less obvious ones. "Also, Syene can't possibly be exactly on the Tropic of Cancer. That means that the distance between Syene and Alexandria is a little over or under one-fiftieth of the earth's circumference."

"You are all correct," Risu said, nodding, "although the exact positions of Syene and Alexandria were probably the smaller problem. As you've pointed out," he nodded in the direction of the Head Boy, "distance measurements on land were very unreliable. Nowadays, with satellites and aeroplanes, measuring the distance between two points on Earth is rather trivial. But in the time of Eratosthenes, a linear distance was extremely difficult to procure. But even so, Eratosthenes' estimate was valid for a very long time, and it's one of the most famous scientific experiments of the entire ancient world."

Quote:

Originally Posted by -Bambi-

Kel shook his head at his notes, which were pretty much a mess of numbers and words that Kel didn't exactly understand. Sure, he liked astronomy, but things like this confused him. He liked 'Which planet is this? Which planet is this?' much more. But of course, that would've been too easy, huh?

Limitations? He raised a hand. "It...took a lot of time, work, and effort?" he answered, not exactly sure if those things counted as limitations. But, hey, at least he tried.

Risu chuckled. "It certainly did take a lot of time, but those were probably not limitations to Eratosthenes. He compiled a three-volume encyclopaedia on geography, and I would guess that that took him much longer than calculating the Earth's circumference. All he had to do was wait for the distance estimate between Alexandria and Syene."

He clapped his hands. "And with that, we shall conclude this lesson. Homework... is on the board." He flicked his wand over his shoulder, and writing appeared. "An essay on your evaluation of the scientific method, or, if you are artistically inclined, a detailed sketch and explanation of Eratosthenes' famous experiment." He dropped his wand on the desk. "Thank you all for coming. If you have any questions about the lesson or your homework, I'll be available in my office."

Risu began gathering his things.

Homework

Choose one:

Write a short essay discussing the merits and limitations of the scientific method. (3+ paragraphs)

Give a detailed explanation, including an original drawing, of Eratosthenes' calculations of the circumference of the Earth.

Homework can be handed in until 11.59pm GMT on Saturday, 29 May. This assignment is worth up to 15 points.

OOC: Make sure to read the submission guidelines carefully.

05-15-2010, 06:15 PM	#164 (permalink)
Antarctica Welsh Green Join Date: Aug 2007 Posts: 24,627	Encyclopaedia Galactica Quote: Originally Posted by BluePhyre Phyre listened to the correct answers and sighed, raising her hand to try again. "If any calculations had gone wrong, the entire measurement could be off," she said shakily. "Furthermore, if he had used a different amount as a stadia, then he would have been wrong, and yet credited to this day to be extremely accurate, as accurate as one could be with the technology available at the time. Because of the differing measurement systems and opinions within the same measuring system, his method, while perfected by himself, would not be able to be used by many others of his time. While it's not a limitation on Eratosthenes himself, it would effect his method." "I agree, but we are the ones who don't know how much a stadium was. Eratosthenes was certainly aware of the length of one, but that knowledge has been lost. But if we take his value of 5000 stadia for the distance between Alexandria and Syene, then we can get an approximation of how long he and his contemporaries thought a stadium was." SPOILER!!: Quotes Quote: Originally Posted by feltbeatslover22 Trixie raised her hand. "Do you mean how he can't be exactly right?" she asked. "Well for a start Syene isn't exactly on the Tropic of Cancer, but slightly North, and he used this in order to make his measurements. And as I mentioned just a minute ago, Alexandria isn't exactly south of Syene. The last is that the sun appears as a disk located at a finite distance from the earth instead of as a point source of light at an infinite distance" she siad sounding like a ravenclaw. Woah. "So therefore the distances weren't exactly reliable" she smiled. "But giving him credit, his measurements were extremely close to the actual measurements. Which as you said was pretty impressive for a guy of his era" she giggled. Quote: Originally Posted by xiiWishiWasYours "Some limitations were that overland distances weren't reliable because of the travel on the Nile river, they were also not completely accurate because of the locations were not exact as well, but an estimate," Selena tried. Quote: Originally Posted by Harry174 Simon put up his hand. "the accuracy of his calculation was limited. The accuracy of Eratosthenes' measurement would have been reduced by the fact that Syene is slightly north of the Tropic of Cancer, is not directly south of Alexandria, and the sun appears as a disk located at a finite distance from the earth instead of as a point source of light at an infinite distance. " He said before continuing. "The greatest limitation to Eratosthenes' method was that, in antiquity, overland distance measurements were not reliable." Simon hoped that he was right but wasn't sure. Quote: Originally Posted by DanialRadFAN01 Chris raised his hand to answer the Astonomu Professor's question, "Professor, a limitation of his method was that the angles like that can only be measure at about a quater of a degree and the distances that he covered on land were not reliable enough to make the equation work out correctly." the Gryffindor stated. It was too bad really, the man was a good thinker for the time at least. Quote: Originally Posted by Zecaar Santi was surprised at how he actually liked it when a professor agreed with him. He'd never been one for participation before. But deciding to give it another go, he raised his hand. "That it can't be used for much else," he suggested. "Not to mention its lack of accuracy. Any error would multiply by fifty times due to scaling up." Santi sat back again. Okay, that was it. He was done talking... perhaps. He had no idea why, but this astronomy discussion made him want to input... why would that be? Quote: Originally Posted by Poisonedbyyou Limitations, now. Abby thought for a moment. "Of course, there's the obvious one," she said. "By step counting, the distance he found between Syene and Alexandria couldn't be perfectly accurate." Now for the less obvious ones. *"Also, Syene can't possibly be exactly* on the Tropic of Cancer. That means that the distance between Syene and Alexandria is a little over or under one-fiftieth of the earth's circumference." "You are all correct," Risu said, nodding, "although the exact positions of Syene and Alexandria were probably the smaller problem. As you've pointed out," he nodded in the direction of the Head Boy, "distance measurements on land were very unreliable. Nowadays, with satellites and aeroplanes, measuring the distance between two points on Earth is rather trivial. But in the time of Eratosthenes, a linear distance was extremely difficult to procure. But even so, Eratosthenes' estimate was valid for a very long time, and it's one of the most famous scientific experiments of the entire ancient world." Quote: Originally Posted by -Bambi- Kel shook his head at his notes, which were pretty much a mess of numbers and words that Kel didn't exactly understand. Sure, he liked astronomy, but things like this confused him. He liked 'Which planet is this? Which planet is this?' much more. But of course, that would've been too easy, huh? Limitations? He raised a hand. "It...took a lot of time, work, and effort?" he answered, not exactly sure if those things counted as limitations. But, hey, at least he tried. Risu chuckled. "It certainly did take a lot of time, but those were probably not limitations to Eratosthenes. He compiled a three-volume encyclopaedia on geography, and I would guess that that took him much longer than calculating the Earth's circumference. All he had to do was wait for the distance estimate between Alexandria and Syene." He clapped his hands. "And with that, we shall conclude this lesson. Homework... is on the board." He flicked his wand over his shoulder, and writing appeared. "An essay on your evaluation of the scientific method, or, if you are artistically inclined, a detailed sketch and explanation of Eratosthenes' famous experiment." He dropped his wand on the desk. "Thank you all for coming. If you have any questions about the lesson or your homework, I'll be available in my office." Risu began gathering his things. Homework** Choose one: Write a short essay discussing the merits and limitations of the scientific method. (3+ paragraphs) Give a detailed explanation, including an original drawing, of Eratosthenes' calculations of the circumference of the Earth. Homework can be handed in until 11.59pm GMT on Saturday, 29 May. This assignment is worth up to 15 points. OOC: Make sure to read the submission guidelines carefully. __________________