Tech WondersPlay

Energy, Heat & MotionWaves

Count the Thunder

Lightning tells you how far away the storm is

The sky flashes, and a few heartbeats later comes the boom. What is that pause quietly telling you about the storm?

You'll find out

  • What the pause after a flash measures
  • Why lightning makes any sound at all
  • When a storm is too far to hear

Why it matters

Counting the seconds after a flash tells you whether a storm is closing in, and when it is time to head indoors.

About 3 min6 interactive slides · 5 questionsLesson 112 · Zone 13

Play this lesson

Free to play in your browser or on iPhone

More in this zone

  1. 109Planetary ScienceSaturn Would FloatThe giant planet is less dense than water
  2. 110FractalsRandom Dots Draw a TriangleA game of chance draws a perfect fractal
  3. 111Text EncodingEmoji Are Secret SumsA family emoji is several emoji glued together
  4. 113Engineering DesignWhy Manholes Are RoundA round cover can never fall into its own hole
  5. 114GeometryThe Drill That Makes Square HolesA rounded triangle can drill an almost square hole
  6. 115ProbabilityWhy Casinos Always WinOver enough bets, a small edge becomes a certainty
  7. 116Music AcousticsWhy Some Notes Sound Good TogetherPleasant chords hide simple ratios
  8. 117Computing HistoryThe First Bug Was a Real MothIn 1947 engineers taped a moth into their logbook