Half-Life Explained

If you cannot tell when one atom will change, how do scientists predict millions of them?

Your turn!

Question 1 of 2

What is a half-life?

The story

Quarky lines up a giant bowl of jittery atoms and starts a stopwatch. No single atom will say when it plans to pop, but after a certain amount of time exactly half the bowl has changed. Wait the same amount of time again and half of what is left changes too. Quarky calls this magic waiting time the half-life, and it is how scientists date dinosaur bones and ancient campfires.

What you'll learn

Radioactive atoms change at random, one at a time
A half-life is the time it takes for half of a big group to change
Each half-life removes half of whatever is left, so some always remains for a long time
Half-lives let scientists measure the age of rocks, bones and old objects

Quarky ⚛️ Quantum Physics ⚡ Energy