Eratosthenes Proves the Earth is Round скачать в хорошем качестве

Eratosthenes Proves the Earth is Round

One of the greatest experiments ever. As Carl Sagan said, all it took were some sticks and shadows, some math and some brains. Let me explain! Have you class consider some of the following: 1. On a sunny day, go outside and determine the size of the Sun. Using a tube of rolled up paper, place some aluminum foil over one end and some graph paper over the other. Put a small pinhole in the centre of the foil. Hold the tube up directly at the sun. You should get an image of the sun passing through the foil onto the graph paper. Measure the image using the grid on the graph paper. Since you know the length of the tube and the diameter of the image, you can set up equivalent fractions: diameter of image over length of tube = diameter of Sun over 150 million kms. Another brilliantly simple yet effective experiment using the Sun. 2. Have students research a man named Aristarchus of Samos. What was his philosophy of the heavens? What made him unique for his time? Was he alone or did others agree with him? What was the opposing view? Which view held most sway over society at the time? 3. In groups of 2 or 3, have students take different size balls (soccer ball, baseball, ping pong ball etc.) outside on a sunny day. Have them simulate a lunar eclipse. The Sun can be "the Sun" of course, while the central person can hold up a ball to represent the Earth and the other can hold a smaller ball to represent the Moon. Simulate a lunar and a solar eclipse. Notice the size and shape of the shadows of each object? Note that the Earth's shadow covers the entire Moon while the Moon shadow does not cover the entire Earth. This is why a solar eclipse is far more rare to see than a lunar eclipse. 4. Have students draw the experiment conducted by Eratosthenes. Place a large "Sun" on the edge of a page with parallel light rays coming off it towards the Earth. Draw the two sticks on the Earth. One will be in line with the rays, the other not due to the curve of Earth. Note the angle formed between the rays and that stick. The stick lines can be extended to the centre of the Earth where they will intersect. The angle formed there was found to be about 7 degrees. Now do the math. This will require an understanding of fractions. 5. Have a discussion about why there are still people who believe the Earth is flat. Research what their reasons are and then have students defend or rebutt these reasons. It should make for interesting class discussion.