Wednesday, April 27, 2011

Walking Trought Pocemin Silver

ACTIVITY 5: Eratosthenes. MEASUREMENT OF THE RADIUS OF THE EARTH.

Whenever
read the second chapter of the same title as this activity book "From Archimedes to Einstein" I recommend you see the video that follows that will serve to clarify some doubts:




Already prepared to complete the questionnaire on the chapter you just read:

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Now it is put into practice what they learned and to mark the International Year Astronomy (held in the year 2009) going to become Eratosthenes, with many more technical, and we determine, as he did over 2000 years ago, as the circumference of the Earth. What do we need? We take the measure of the length of the shadow cast by a wand (and its own length) in two places on our planet that are roughly on the same length. These measures should be taken simultaneously to the experiment comes out the best possible ... But better that you see the following video explaining the procedure that we follow (until minute 8:10):




Have you seen the full video? Perfect, then you know that we will participate in a project that transcends the boundaries of the school. With the help of many people (students like you) in Spain we will determine the radius of the Earth.
What day?, 23 March.
Where?, In the patio dining.
What time?, From 11:30 to 14:00.

In case you have any doubt in the following presentation explains the whole process that we follow.



Well, what now? With the data we have taken we obtain the radius of the Earth in two ways:
1. Flushing the data on page project website : the angle subtended by the shadow when the sun was at its zenith ( height of the sun at noon ) and distance to the parallel 40 º N (Google Earth is a good choice) . You can see the result here. This part of the Angel and Victor do with your help. For how do it again to see the video from the minute 8:10.
2. Using experimental data (must obtain average values) on the measure for all / as you / as and those of other college (keep in mind that the angle that the angle obtained is the height Sol so you have to figure out what interests us to do the calculations) and of course following the process Eratosthenes used you have read in the corresponding chapter of book reading. This second part is that it is up to you. Pay special attention to the population eligís, reminds you to be as close to the meridian passing by our school (compare the data length) for the data you serve. For this process you should find the location of schools until you find which is best suited (look online) and check the latitude and longitude with Google Maps . To do this you must add the tool Position Finder. To calculate the distance between the two schools can use any of the Google Maps tools.
Another option is to download Google Earth and install on your computer.
Because you will be hard to pass any college involved exactly the same meridian, as an improvement to the task can try to deduce the gap angle that occurs from one meridian to another with the aid of information provided by and sta website. Remember that in this case you can not use the straight line distance between the two schools but must take the value in a straight line to the latitude of the center of their choice.
With the data, calculations, videos, explanatory graphics, photos etc generaréis a new entry in your blog where explicaréis: the experimental procedure followed (data collection in the courtyard and getting the angle in the laboratory hall) and the calculations made to obtain the radius of the Earth.

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