What Is a Leap Second? | National Geographic?

A leap second is like adding one extra second to our clock so it stays in sync with time itself.

Imagine you're playing a game of tag with your friends on a playground. Every day, you all count to 60 and then start over. But sometimes, the sun takes just one extra second to rise, like it's giving you a little head start. To keep up, you add that one second to your counting so everyone stays fair.

Our clocks are like the playground’s timer, they count seconds neatly and evenly. However, Earth doesn’t always spin at the same speed. Sometimes it slows down just a tiny bit, like when you take a deep breath before running. That slowdown makes our clock go just one second ahead of real time.

To fix that, scientists add a leap second, like adding an extra second to your timer so it matches how long Earth actually takes to spin around once.

It’s not often, only sometimes, but when they do, we get to experience time being just a little more precise. It's like giving the Earth a tiny nudge to keep everything in balance!