Count the Seconds Between Lightning and Thunder
Thunder is the sound made by lightning. The gap between flash and sound tells you how far away the strike was.
Thunder is the sound produced when lightning heats the air so violently that it expands as a shock wave. The delay is useful: sound travels about a kilometre in three seconds, so counting the seconds between flash and rumble and dividing by three gives the distance in kilometres. Divide by five for miles.
- The sound of lightning. *A clap of thunder.*
- To make such a sound. *It thundered all night.*
- Steal someone's thunder — take their credit. *He stole her thunder.*
Word forms
| Form | Word | Example |
|---|---|---|
| Noun | thunder | Distant thunder. |
| Verb | thunder | It thundered. |
| Adjective | thunderous | Thunderous applause. |
| Compound | thunderstorm | A summer thunderstorm. |
| Related | lightning | A lightning strike. |
How it is used in a sentence
- Thunder followed six seconds later.About two kilometres away.
- There was thunderous applause.Very loud.
- She stole his thunder by announcing first.Took the attention he expected.
Storm facts
- Three seconds per kilometre — the counting rule
- Lightning is hotter than the sun's surface — briefly, in the channel
- Thunder is the shock wave — from air expanding explosively
- Sheet lightning — a flash hidden by cloud
- Thor — the Norse thunder god behind Thursday
From Old English *thunor*, related to the Norse god Thor and to Latin *tonare*, to thunder. Thursday is Thor's day, named for the same thunder.
How far away is the lightning?
Count the seconds between flash and thunder. Divide by three for kilometres or by five for miles.
Where does *steal someone's thunder* come from?
From the playwright John Dennis, whose stage thunder machine was used in another production after his own play failed.