Thunder & Lightning
As thunderclouds swell, electricity builds up. Sometimes you can see a spark of electricity jumping from one cloud to another. And when itjumps to earth there’s a flash of lightning.Thunderclouds develop from cumulo-nimbus clouds. Electricity is built up inside the clouds and then is suddenly discharged into the air. Known as lightning, the discharged electricity has an enormous force: as much as several million volts
Why don’t the Thunder & Lightning come together?
If lightning is very close you hear the thunder at almost the same time. But if it’s far away the sound of the thunder comes a few seconds later. That’s because light travels much, much faster than sound. Lightning heats the air, causing it to expand rapidly & collide with the air around it. The sound of that collision is heard as a sharp crack if lightning is close by. If it is distant, the sound changes to a rumble by the time we hear it. In one second, light can travel around the earth seven & a half times, but sound travels only about 330 metres. That is why we can see lightning before we can hear the sound of it.
Where does lightning strike?
Lightning usually strikes tall objects like buildings & trees. Lightning will also strike metal objects, even, occasionally, the metal tip of an umbrella. If you’re playing in an open field or park where there are no tall objects, you should go inside if thunderclouds appear. If you’re swimming, get out right away.
Places where lightning is a danger
- In an Open field where you may be the tallest thing around.
- Near tall trees.
- High on a hill or mountain.
Places that are safe
- Most large buildings are protected by lightning rods, so you’re safe inside.
- Lightning doesn’t usually strike vehicles, like cars and buses, if the doors and windows are closed.
When a thundercloud approaches, electricity is discharged by objects that are tall, made of metal or electrically charged. These are likely to be struck by lightning, which is an enormous discharge of electricity from a thundercloud. Such objects should be avoided when thunder is heard because the voltage in a bolt of lightning can easily cause death.