Pendulum Foucault, Sun and us.

What is this---the Pendulum Foucault?
It is just a pendulum, you know, but also important and sensational one......
You know, Earth spins. But, before Nicolaus Copernicus in 16th people think Sun go around Earth. It was very likely, and it is likely for us without study about physic. Today, I want to show easy experiment to prove Earth spins. It is the Pendulum Foucault.


On February 1851, in Pantheon de Paris, Foucault held experiment. He isn't professional scientist, but he is very skillfull to have scientific experiment. He had had a preliminary experiment in his house before the experiment in Pantheon de Paris.
Foucault's hypothesis is about Earth's spin and a pendulum. At that time, although Earth goes around Sun but there are no method to prove that by physical. His hypothesis uses "Coriolis power". What is this?
Coriolis power do NOT really exists, but we can see this. Coriolis power is made by missing the fact we are on the Earth. Please imagine a disc and a ball on the center of disc. And rotate a disc and roll a ball out of disc straightly and see from above these. OK, you saw the ball is go straightly.  Then please see from the disc, you are also rotating. Or to imagine, you can use a merry-go-round, a ball is rolled from center of it and you run by speed is same a merry-go-round. What you see? It is "the ball makes a curve"! This is Coriolis power. There is no power, but we thinks there IS power. Because it is easy to think.
Go back to Foucault Pendulum. His hypothesis is "If Earth spins, Coriolis power will be observed, and it is expressed by a pendulum's orbit. Coriolis power makes it off to the side (except for the equator). " He set a big pendulum in Pantheon de Paris. Finally, the pendulum's orbit was off to the side. Earth is spinning!



See also......
http://www.calacademy.org/products/pendulum/
http://en.wikipedia.org/wiki/Foucault_pendulum