Um Mosaico de Ciência e Cultura

A Mosaic of Science and Culture

http://www.mosaicofscience.co.nr/

This is the official website of our project

To determine the Earth measure through the technique of the star height

· We choose two cities, A and the B, that are in the same meridian;

· nWe’ve chose the cities of OPorto (A) and Aveiro (B) located in the meridian 8º 32'W and 8º 42'W, respectively.

· nWe measure the distance (d) between A and the B (we measure the length of Earth arc from A to B)

· Observing d on a map (OPorto-Aveiro) = 68 Km

· We choose a star X, visible from A and B, and we measure the height of X in A and the height of X in B; them, we determine the angle Ø that represents, in degrees, the difference between these two heights;

· The chosen star was the Sun - two poles were stuck in the ground, one in the OPorto and another one in Aveiro, at the same hour we determined the shade projected by the poles (52 cm in A and the 53.1 cm in B).

· To the corresponding angle to the height in A is = 33,32 º

· The corresponding angle to the height in B is = 33,93 º 

· nØ = 33,93 º - 33,32 º = 0,61

http://www.avert.pt/clubeeuropeu

This is the website Comenius of Portuguese school (in construction)

 

See also

Performed Calculus

n   Using the proportionality between arc length and measure of the corresponding angle, we have that

n   p = 360. d Ø; where p corresponds to the perimeter of the earth.

n   d (A-B) =  68  km

n   Ø =   0,61 º

n    p = 360 x 68 / 0,61 = 40131,15 km

     p = ƒΞ. D ↔ D = 40131,15 km/ 3,14

     Diameter = 12 780, 6 Km