Discover how the Foucault Pendulum of the Museu de les Ciències interactively demonstrates the Earth’s rotational movement

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On the first floor of the Museu de les Ciències, a pendulum hanging from the the top of the roof structure, and with a circular base, demonstrates that the Earts rotates on it own axis,

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The historical origin of the experiment

The French physicist Bernard León Foucault in 1851, at a public exhibition at the Pantheon in Paris, suspended a 67 meter long pendulm from which hung a 28 kilogram cannonball. Attendees watched in awe as the plane of motion of the pendulm slowly turned clockwise, revealing the rotation of the Earth.

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Technical characteristics of the Valencia pendulum

Cable length: 30 meters (one of the longest in the world)

Full spin cycle: 34 hours

Direction of turn: Clock hands (slow but steady spin)

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In reality, it is not the pendulum’s oscillation plane that turns, but the Earth and with it, the whole Museum moves «around» the pendulum.

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Why does the pendulum never stop?

When we move the pendulum from its equilibrium position, the only force exerted on it is the gravitational pull over its mass. However, friction – both of the wire and of the air – would eventually stop the oscillation altogether.

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The secret of its movement: The oscillation of the pendulum does not dampen due to an electromagnetic system located on the roof that keeps its oscillation constant. This allows, over time, to observe its turn.

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Thanks to Foucault, we know that it is an illusion: it is the building – and with it the entire planet – that actually spins “under” the pendulum. Everything around us revolves, with the planet, every 24 hours. In addition, the Earth revolves around the Sun, and the Sun and its planets around the Milky Way… But Foucault’s pendulum ignores all these movements: it is aligned with the universe.