Word Count

Writers Talk About Writing

When Lightning Strikes, What Does Air Do?

Stan Carey, a professional editor from Ireland, writes entertainingly about the English language on his blog Sentence First. Here a children's book about weather leads Stan to ponder which English words best describe what happens to air when it is heated by lightning.


Burst after burst the innocuous thunders brake.
— Robert Southey

John Farndon's Weather: How to Watch and Understand the Weather and its Changes is a charming children's book published as part of DK's Eyewitness Explorers series. On page 47 I read the following line:

Thunder is the sound of air bursting as it is heated rapidly by lightning.

The description struck me as strange, because I'm used to thinking of superheated air not bursting but expanding rapidly or violently to form a pressure wave that causes the sound of thunder. There is a sense in which burst can mean expand rapidly, but it more usually means something like explode or tear, or surge in more figurative contexts. That is, it tends to imply a physical membrane or boundary that is opened, ripped, broken, split, shattered, and so on; there is usually a sense of boundary-breaking, albeit one that varies greatly in intensity and abstraction.

Some examples will help us examine the semantic constellation of burst. Tomatoes that are bursting with ripeness burst in our hands or in the microwave. A tree's roots burst slowly through concrete; the sun bursts through the clouds; swollen rivers burst their banks; the Hulk's clothes burst at the seams; a sportsman makes a burst of speed to burst through the opposing defence; a busy room fills to bursting (point), whereupon the nearest person to the door might burst it open. The recurring sense of rupture or explosivity is evident in this word map from the Visual Thesaurus:

People burst into song when their hearts are bursting with joy, and they burst into shivers if a window bursts open on a cold day; they burst into tears if their hair bursts into flame, and they burst into laughter (or "burst out laughing") when a burst of amusing data enters their minds. We hear bursts of conversation and bursts of gunfire. We see bursts of activity, such as sudden bursts of rain or sunshine. When air or another gas bursts, it is usually from something, such as a tyre, bubble, balloon, nail gun, or a mouth in the act of blowing out a candle (though a puff is usually enough).

The sound of thunder can be a clap, crack, peal, snap, roll, or rumble; each term has its own nuances. But to explain the sound as air bursting is, I think, inferior to expanding rapidly or some such phrase that would minimise the possibility of fuzzy or misleading interpretations. Especially since many people — not least children — are afraid of storms, and air bursting carries more alarming connotations than does air expanding (slight semantic overlap notwithstanding).

Am I being foolish, fussy, or fair? Have I made a storm in my afternoon teacup?

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Stan Carey is a scientist turned freelance editor from the west of Ireland. He shares his fascination with language, words and books on his blog, Sentence first, and on Twitter. Stan has a TEFL qualification, a history of polyglottism, and a lifelong love of stories and poetry. He writes articles about the English language for Macmillan Dictionary Blog. Click here to read more articles by Stan Carey.

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