How Does Carbon Dating Determine Age?

The Cosmic Clock

Imagine every living thing carries a tiny, ticking clock made of invisible particles. When you are alive, your body constantly swaps carbon with the air around you, keeping that clock steady. But when you die, the swapping stops, and the clock starts to tick down.

How It Works

The secret lies in carbon-14, a special type of carbon atom that is slightly different from others. While you are alive, plants eat carbon-14, and animals eat plants, so your body stays full of it. Once you pass away, the supply cuts off. The extra carbon-14 atoms begin to break apart over time. Scientists can look at a bone or a piece of wood and count how many special atoms are left compared to normal ones. If only half are left, they know about 5,700 years have passed. This process helps us figure out exactly when ancient people lived or when animals went extinct.

Why It Matters

This method is like finding a diary entry in the ground. It tells us not just that something is old, but how old, helping us build accurate timelines of human history and natural changes.

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Examples

  1. A wooden beam from an ancient house still holds carbon-14 atoms that count down like tiny sand timers.
  2. Scientists look at a fossilized leaf to see how much of its original special carbon has turned into nitrogen.
  3. If you found a bone with half the usual amount of this isotope, it means about 5,700 years have passed since the animal died.

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