Questions kids askSky and weather

What is lightning?

Lightning is a giant spark of electricity that jumps through the air when the electric charge built up inside a storm cloud grows too strong for the air to hold back.

How to explain it, by age

This is how Pukki answers the question, once for each of the five age bands it speaks to. Pukki is a voice-first AI encyclopedia for kids: a child asks out loud, and it gives a short spoken answer made for their age.

For a 3- or 4-year-old

Lightning is a big, bright spark in the sky. It happens when tiny bits of ice bump together inside a storm cloud and make a giant zap, like static on your hair.

Edited. Pukki said “It happens when clouds rub and make a giant zap.” Clouds do not rub against each other. The charge builds inside one storm cloud, where bits of ice collide. (National Weather Service)

For a 5- or 6-year-old

Lightning is a huge spark of electricity in the sky. It happens because storm clouds build up electricity, then it suddenly jumps through the air, like a tiny spark from a jumper but much, much bigger.

For a 7- or 8-year-old

Lightning is a giant spark of electricity in the sky. Inside a storm cloud, tiny ice pieces and water drops bump together, building up electric charge until it suddenly jumps through the air as a bright flash. Thunder is the air making a loud bang after the lightning heats it very quickly. Want to know why lightning often comes before thunder?

For a 9- or 10-year-old

Lightning is a giant spark of electricity in the sky. Inside a storm cloud, tiny ice and water pieces crash together and separate electrical charges, then the charges suddenly jump through the air as a bright flash. A lightning bolt can heat the air to about thirty thousand degrees, making the air expand quickly and causing thunder.

For an 11- or 12-year-old

Lightning is a huge spark of electricity in the sky, usually inside a storm cloud or between a cloud and the ground. Ice and water drops bump around in the cloud and separate electric charges, until the charge difference becomes strong enough to force a path through the air. The air heats to about thirty thousand degrees, making it glow, and that sudden heating makes thunder.

A little more, for you

Inside a thunderstorm, rising ice crystals collide with soft hail called graupel. The crystals come away with a positive charge and the graupel with a negative one, and the storm’s winds carry them to different parts of the cloud. When the difference grows too large, a spark jumps: inside the cloud, between clouds, or down to the ground.

Lightning can heat the air it passes through to about 50,000 degrees Fahrenheit, roughly 28,000 degrees Celsius and five times hotter than the surface of the Sun. The air expands so fast that it makes the sound we hear as thunder. Light travels far faster than sound, so the flash reaches you first.

Questions to ask them

What did the last lightning you saw look like?
Which comes first in a storm, the flash or the bang?
Have you ever felt a tiny zap from a sweater or a door handle?

These two parts are ours. In the app, Pukki writes its own for every answer, under “Explain it to me” and “Ask them back”.

Try it together

Watch a storm safelyCount the seconds between a flash and thunder from indoors.

Pukki’s own idea, given to the parent with one of the answers above.

One more why

Where these answers come from

We asked Pukki this question ourselves, once for each age, on 2 October 2026. No child’s question is published here. The answers are written by AI, and we read each one against the sources below. One of the five is marked Edited, with what we changed and why.

Pukki’s answers vary from one asking to the next, and can be wrong. It answers in the English its device is set to; these were asked in Australian English. Today Pukki also ends most answers with a short question on the same topic, which a parent can turn off.

Read against these sources on 5 October 2026.