It is called a non-conductor of electricity.
What substances are non-conductors of electricity?
Gutta-percha, sulphur, glass, silk, wool, hair, feathers, cotton, and paper.
What is lightning?
Lightning is electricity passing from one place to another.
When does lightning pass from one cloud to another cloud?
Whenever one cloud becomes filled with more electricity than another, the cloud having the most electricity gives off a portion to the cloud having the least electricity.
When does lightning pass from the earth to a cloud?
Whenever the earth contains more electricity than the cloud does.
When does lightning pass from a cloud to the earth?