In 1851, a French physicist suspended a metal ball from a 67-metre wire, and it became one of the first direct proofs that the Earth rotates

Most of us accept that the Earth rotates because we have been taught it since childhood.

We have seen satellite images, watched footage from space and learned about day and night.

But imagine living in the middle of the 19th century, when none of that evidence existed.How could you convince an ordinary person that the ground beneath their feet was constantly spinning?In 1851, French physicist Léon Foucault answered that question with remarkable elegance.

Rather than relying on complex mathematics or astronomical observations, he suspended a heavy metal sphere from an exceptionally long wire and let it swing.

Hours later, something extraordinary seemed to happen: the pendulum appeared to change direction on its own.