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Thunder & Lightning

Know that thunder and lightning happen during thunderstorms: lightning is a giant spark of electricity that forms in clouds, thunder is the sound the lightning makes, and we see lightning before hearing thunder because light travels faster than sound

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What a learner can do afterwards

  • Describe lightning as a large electrical discharge in clouds
  • Explain that thunder is the sound caused by lightning
  • State that we see lightning before hearing thunder because light travels faster than sound

1 · Read

Lightning is a giant spark of electricity that builds up inside a storm cloud that grows from the puffy clouds you know. When it jumps out, it lights up the sky in a bright flash. Thunder is the loud sound that comes right after. It is the sound the lightning makes as it rips through the air. Thunder fades with distance, so a far storm may flash with no boom.

Flash!......Boom!
First you see the flash. Then, after a moment, you hear the boom. Light always reaches your eyes before sound reaches your ears.
Try it together

Anna is safely inside when a storm rolls in. She sees a bright flash of lightning through the window and starts counting: one, two, three, four. Then she hears a deep boom of thunder. The lightning and thunder happened at the same moment inside the cloud. Anna saw the flash before she heard the boom, because light travels much faster than sound. Light feels instant; sound takes the extra seconds.

Start togetherFlash arrivesBoom arrives
Good to know

Next time you are safely inside during a storm, try counting the seconds between the flash and the boom. The count does not change what happened. It only shows how long the sound took to reach you, since light gets to your eyes almost instantly and sound takes much longer.

Lightning is electricity, thunder is its sound, and you always see the flash before you hear the boom.

The rewritten readings were written for this dataset.

2 · Watch

Take it off screen

Print a worksheetA4 with an answer key page for grown-ups. No screen, no internet.

Where it sits

Where this leads

Jobs that lean on this skill. Follow one to see everything it is built on.

Then practise

8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.

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Thunder & Lightning · Science, ages 7 to 9 · LightMySky