Mochi Isle
Thunder & lightning · Mochi IsleScience for kidsWhat makes lightning and thunder?
In short: Lightning is a giant spark of electricity built up inside a storm cloud. It heats the air so fast that the air bursts outward, making thunder. Light travels far faster than sound, so the flash reaches you first.
How it works
Storm clouds are tall and wild inside. Air rushes up and down, and bits of ice and soft hail keep crashing into each other. These bumps build up electric charge: the top of the cloud usually becomes positive and the bottom negative. When too much charge builds up, it jumps out in a huge spark, inside the cloud or down to the ground.
The thin path of air that lightning travels along is heated in a split second to several times hotter than the surface of the sun. The air expands so suddenly that it bursts outward, and that is the boom of thunder. Close by it cracks; far away, sound from different parts of the long flash arrives at different times, making a long rumble.
Light is incredibly fast, so the flash reaches your eyes almost instantly. Sound is much slower, taking about 3 seconds to travel 1 kilometre. Count the seconds between the flash and the thunder, divide by 3, and you have roughly how many kilometres away the storm is.
Where to see it in New Zealand
New Zealand gets fewer thunderstorms than tropical places, but they still happen, sometimes on hot summer afternoons and sometimes when cold air sweeps in. Weather forecasters issue thunderstorm warnings, so check the forecast before a tramp. In Māori tradition, Tāwhirimātea is the god of the weather, including storms.
Try it together
On a stormy day, stay indoors and watch from a window. When you see a flash, start counting seconds. Stop when you hear thunder and divide by 3 to get the distance in kilometres. Count a few times. Is the storm coming closer or moving away?
Kids also ask
Is it safe to shelter under a tree in a thunderstorm?
No. Lightning tends to strike tall, lonely things, so standing under a tree is dangerous. The safest places are inside a solid building or a hard-topped car with the windows up.
How long should I wait after thunder before going outside?
A common rule is to wait about 30 minutes after the last thunder you hear. If you can still hear thunder, you are close enough for lightning to reach you.
In the game, “Thunder & lightning” is a nature card on Mochi Isle.
Your child finds this card by reaching the right place or meeting the right weather on the island, and lights it up by answering the question on the back. Tap the button below and the game shows your child which island it is on and how to find it. Mochi Isle is a browser learning game for ages 5 to 18; the main island and the daily lesson are free.
Find “Thunder & lightning” on the island ↗ All cards from Mochi Isle