Science labs › Physics › Storm over the Town
Where will the lightning strike? Watch it feel its way down, then add a lightning rod.
Storm over the Town lab · Last updated: 16 October 2026
You watch a storm build over a small town, see lightning feel its way down from the cloud and guess where it will strike. Then they add a lightning rod and see how it changes the result. It turns a frightening event into something they can understand and stay safe around.
What you'll discover
- Storm clouds build up huge separated electric charges, and lightning is a giant spark that lets them flow.
- Lightning creeps down in branching steps before the bright main flash joins cloud and ground.
- Tall, pointed, well-earthed objects such as lightning rods give the strike a safe path to the ground.
The science in plain words
Inside a thundercloud, strong rising air carries water droplets and ice up and down. When ice pellets and ice crystals collide, electric charge is transferred between them. Lighter, positively charged crystals are carried to the top of the cloud, while heavier, negatively charged particles gather lower down. The ground beneath gains an opposite charge. When the difference becomes large enough, the air can no longer insulate and a spark jumps.
Lightning does not appear in one go. A faint channel called a stepped leader works its way down from the cloud in short, branching jumps, which is why lightning looks forked. As it nears the ground, upward streamers rise from tall objects such as trees, towers and buildings. When a leader meets a streamer, the path is complete and a powerful return stroke flashes up the channel. It heats the air to around 30,000 °C, and the air expands so violently that we hear thunder.
A lightning rod is a metal rod on the highest point of a building, connected by a thick wire to a plate buried in the earth. It does not attract lightning from far away, but if lightning strikes nearby it gives the current an easy path to the ground, so it does not pass through the building and start a fire.
Where it fits
- India, NCERT: Goes beyond the NCERT syllabus for classes 6 to 10; it builds on the electricity chapters in classes 7 and 8.
- United States: Grades 6 to 8
- Next Generation Science Standards: MS-PS2-5, MS-ESS3-2
Common questions
What causes lightning?
Collisions between ice particles inside a thundercloud separate electric charge, with positive charge collecting near the top and negative charge lower down. When the charge difference between the cloud and the ground, or within the cloud, grows large enough, the air breaks down and a giant spark flows.
How does a lightning rod protect a building?
A lightning rod is a metal rod on the highest point of a building, joined by a thick conductor to the ground. If lightning strikes, the current flows harmlessly down this path into the earth instead of through the walls, wiring or roof, which could catch fire.
Why do we see lightning before we hear thunder?
Light travels about a million times faster than sound. The flash reaches you almost instantly, while thunder travels at roughly 340 metres per second. Counting the seconds between flash and bang and dividing by three gives a rough distance to the strike in kilometres.
Related labs
- Electric Fields: Charge a metal ball and hang a tiny pith ball beside it. How far does the invisible push move it?
- Weather Patterns: Why does wind swirl round a storm instead of blowing straight in?
- Charge the Flash: Fill a capacitor from a battery. Why does the light start bright and then fade?
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Try it yourself
The Storm over the Town lab is one of the interactive 3D science labs inside Taz. Change one thing, predict what will happen, then run it and watch. Labs open after you sign in.