Sudeshna Sinha

Two pendulums hang side by side, connected by a spring. Give one a push, and through the spring the other starts to swing. That's how the two regions of the equatorial Pacific are arranged, where sea-surface temperature rises and falls in the rhythm of El Niño.

Two pendulums hang from the same wall, with a spring stretched between them. Each on its own can swing or stay still, but connect them and a shared dance begins: one nudges the other, and oscillations spread through the whole setup. That's how the Pacific Ocean works, where two neighboring regions exchange heat through waves.