“And yet it moves!” is famous catch phrase, which was supposedly said in 1633 by the famous astronomer, philosopher and physicist Galileo Galilei. He was forced by the Inquisition to deny his words about the fact that the Earth moves around the sun rather than vice versa.
Today water «Borjomi» will help us to be sure in this fact.
To start with we shall make a model of the pendulum named after Monsieur Foucault. It is very easy to do it. One end of the steel wire diameter of 5 *10-4 m fix in Cardan suspension, then loaded with a mass of 5 kg hitch to the second end of the wire. The length of the wire is 9.47 m. Oscillation period of the pendulum is calculated using the formula.
So, it is about 6 seconds.
The parameters of our pendulum allow us to consider it mathematical. By the way, the plane of swing of the pendulum does not change regardless of external influences (the system is closed as ever). In this case the rotation of the external environment (our planet) entails a ‘turn’ of plane of swing of the pendulum.
Interestingly, the geographical location of the pendulum has an influence on the result of experiment. Thus, at the North Pole (no matter the South or North), the rate of change of plane of swing of the pendulum is 15 ° per hour, and at the equator there is no change, because it is proportional to the sine of the latitude.
This year the model of the pendulum appeared in Kiev. It is installed at the Kiev Polytechnic Institute. The bronze ball weighs 43 kilograms, and the length of the filament is 22 meters. Kiev Foucault pendulum is considered the largest in the CIS and one of the largest in Europe.
Put the bottle of «Borjomi» as a reference point at a distance of 0.3 m from the center of the projection onto the plane of the suspension and 0,015 m from the plane of swing of the pendulum. «Start up» the pendulum. After 17 minutes of careful observations… pendulum brings down the bottle of «Borjomi»!
The thing is that we (rotating with the Earth) see that the plane of the swing of the pendulum rotates around the Earth’s surface in a direction opposite to the Earth’s rotation.