Misunderstanding about the Foucault Pendulum

In summary, Foucault's famous discovery of the Foucault pendulum came about through a bit of serendipity during the construction of a pendulum clock in 1851. He noticed that the plane of oscillation of a vibrating rod remained fixed even as the chuck rotated, inspiring him to explore the relationship between a pendulum's motion and the Earth's rotation. This effect can be better understood by imagining a pendulum stationed at the poles, where the plane of oscillation would remain fixed while the Earth rotates. As for the exact date of the Pantheon experiment, there are conflicting articles stating either March 31st or March 26th, 1851.
  • #1
JeffOCA
49
0
Dear members,

I have a misunderstanding about the Foucault pendulum. In early 1851, Foucault had an insight that led to his famous discovery. This bit of serendipity occurred during construction of a pendulum clock to regulate the drive of a telescope. Foucault had secured a rod in the chuck of a lathe. Perhaps accidentally, the rod was disturbed so that it vibrated. Foucault noticed that the plane of oscillation of the vibrating rod remained fixed in orientation even as he slowly turned the chuck. This observation inspired him with the notion that the vibrating motion of a freely suspended pendulum might somehow be related to the earth’s rotation.

Foucault noticed that the plane of oscillation of the vibrating rod remained fixed even if the chuck rotated. In the Pantheon's experiment, the Earth is the rotating chuck and the rod is the pendulum. So, why the plane of oscillation of the pendulum revolves and why the plane of oscillation of the vibrating rod do not ? I don't understand the logical link between : "the plane of oscillation" and "necessarily it is due to Earth's spining".

Another question :
According to some articles, the Pantheon experiment occurred on March 31st, 1851 but in other articles we can find March 26th, 1851. Somebody knows ?


Jeff
 
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  • #2
JeffOCA said:
Dear members,

Foucault noticed that the plane of oscillation of the vibrating rod remained fixed even if the chuck rotated. In the Pantheon's experiment, the Earth is the rotating chuck and the rod is the pendulum. So, why the plane of oscillation of the pendulum revolves and why the plane of oscillation of the vibrating rod do not ? I don't understand the logical link between : "the plane of oscillation" and "necessarily it is due to Earth's spining".

The logic behind that effect is best imaginable if you think about a pendulum stationed on the north or south pole (with regards to Earth's rotation). As the Earth rotates so does the chuck. But plane of oscillation remains fixed. This is how an inertial frame observer would see it. But from our point of view it seems like chuck is fixed and plane of oscillation rotates (we are observing the pendulum from chuck's frame of reference). I hope this helped.
 
  • #3
Thanks !
Your explanation helped me !

Another question :
According to some articles, the Pantheon experiment occurred on March 31st, 1851 but in other articles we can find March 26th, 1851. Somebody knows ?


Jeff
 

What is a Foucault Pendulum?

A Foucault Pendulum is a device invented by French physicist Jean Bernard Léon Foucault in 1851. It consists of a long pendulum suspended from a fixed point, which allows it to swing freely in any direction. The pendulum's motion is used to demonstrate the rotation of the Earth.

How does the Foucault Pendulum demonstrate the rotation of the Earth?

The Foucault Pendulum's motion is due to the Earth's rotation. As the pendulum swings, the Earth rotates underneath it, causing the pendulum's direction to appear to change. This is known as the Coriolis effect.

Is the Foucault Pendulum affected by other forces or factors?

Yes, the Foucault Pendulum can be affected by other forces such as air resistance, friction, and vibrations from the surrounding environment. These factors can alter the pendulum's motion and may affect the accuracy of the demonstration.

Can the Foucault Pendulum be used anywhere in the world?

Yes, the Foucault Pendulum can be used anywhere in the world as long as it is set up correctly. The pendulum's motion will still demonstrate the Earth's rotation, regardless of the location.

Are there any misconceptions about the Foucault Pendulum?

Yes, there are some common misunderstandings about the Foucault Pendulum. One is that the pendulum's motion is caused by the Earth's magnetic field, which is not true. Another is that the pendulum will rotate in the opposite direction in the Southern Hemisphere, which is also a misconception. The direction of rotation is dependent on the latitude of the location and not the hemisphere.

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