Radioactive Decay Is Measured by Half-Life
Decay is gradual decline or rotting. In physics it names the breakdown of unstable atoms, measured in half-lives.
Decay is gradual decline, rotting, or the breakdown of something once whole. Physics gives the word a precise meaning: a radioactive substance decays at a rate described by its *half-life*, the time for half the atoms present to break down. The process never finishes cleanly — after each half-life, half of what remains is still there, so the quantity approaches zero without reaching it. The Latin root *cadere*, to fall, also gives *cadence*, *accident* and *decadent*.
- Gradual decline. *Urban decay.*
- Rotting. *Tooth decay.*
- Radioactive breakdown. *The decay of uranium.*
- Half-life — the decay measure. *A half-life of 12 years.*
- Decadent — from the same root. *Decadent luxury.*
Word forms
| Form | Word | Example |
|---|---|---|
| Noun | decay | Slow decay. |
| Verb | decay | It decayed. |
| Past | decayed | Decayed wood. |
| Adjective | decaying | A decaying building. |
| Latin | cadere | To fall. |
- Fluoride helps prevent tooth decay.Dental.
- Carbon-14 has a half-life of 5,730 years.Physics.
- The empty mills fell into decay.Decline.
The cadere family
- Decay — to fall away
- Accident — something that falls upon you
- Cadence — the falling of the voice at a phrase's end
- Decadent — falling from a former state
- Cascade — a falling of water
Old North French *decair*, from Late Latin *decadere*, to fall away, from *de-* plus *cadere*, to fall.
What is a half-life?
The time it takes for half the atoms in a radioactive sample to decay. After two half-lives a quarter remains, and so on.
Are decay and decadent related?
Yes. Both come from Latin cadere, to fall. A decadent society was seen as fallen from an earlier state.