Lightning
A huge charge build-up breaks the air's insulation.
Air as an insulator
Air normally does not let electric charges pass. It is an electrical insulator. But the charge in a cloud keeps building up.
What may happen when the build-up becomes very large?
What this lesson covers
The idea
Air normally acts as an insulator, but when the charge build-up becomes very large its insulating property breaks down and a sudden flow of charges, lightning, takes place within a cloud, between clouds, or between a cloud and the ground.
Air as an insulator
Air normally does not let electric charges pass. It is an electrical insulator. But the charge in a cloud keeps building up.
What may happen when the build-up becomes very large?
- The air's insulation breaks down and charges flow suddenly
- Nothing ever happens
- The cloud turns into a solid
Where lightning flashes
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A sudden flow
Air normally acts as an insulator and does not let opposite charges meet. When the build-up of charge becomes very large, this insulating property of air breaks down. A sudden flow of charges takes place and we see a bright flash of light called lightning.
When the charge build-up is very large, the insulation of air breaks down and a sudden flow of charges gives lightning. It can occur within a cloud, between clouds, or between a cloud and the ground.
Notes
When charge builds up very much, air's insulation breaks down and charges flow suddenly: lightning.
Check yourself
Normally air acts as an electrical …
Lightning happens when the …
Lightning can flash …
The bright flash of light caused by the sudden flow of charges is …
- conductor. Normally air does not let charges pass, so it is an insulator.
- insulator — correct. Yes!
- battery. Air is normally an insulator.
- cloud becomes empty. It happens when the build-up of charge is very large and air's insulation breaks down.
- wind stops blowing. It is the large charge build-up that causes it.
- insulating property of air breaks down — correct. Yes!
- within a cloud, between clouds, or between a cloud and the ground — correct. Yes!
- only within one cloud. It can also be between clouds or between a cloud and the ground.
- only between a cloud and the ground. It can also happen within a cloud or between clouds.
- thunder. Thunder is the sound. The flash is lightning.
- lightning — correct. Yes!
- a breeze. The flash is lightning.