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What Makes Lightning Flash Before Thunder Rumbles?
为什么先见闪电后闻雷声？
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Lightning and thunder happen at almost the same instant during a storm, but we see light before hearing sound.
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Light travels at 300,000 kilometers per second, while sound crawls at just 343 meters per second in air.
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That huge speed difference means light reaches our eyes nearly instantly, even from several kilometers away.
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Sound takes about three seconds to travel one kilometer, so counting seconds helps estimate storm distance.
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A flash followed by a five-second delay means lightning struck roughly 1.7 kilometers away.
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Sometimes thunder sounds like a sharp crack—this occurs when the bolt is very close and the sound hasn’t spread yet.
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Rolling thunder happens when sound waves bounce off hills, buildings, and different layers of the atmosphere.
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Studying lightning paths helps meteorologists improve early-warning systems for severe weather events.