The high voltage caused a spark to jump from the key to grounded objects, proving that the cloud was electrified. Franklin's experiment was dangerous and some people who have flown kites in storms have been electrocuted by lightning. Everything around us is made up of atoms. Although atoms are normally electrically neutral, they may become positive or negative ions if they lose or gain electrons. When they move through air toward one another, they form an electric current that causes a spark.
Lightning is a giant electrical spark in the sky.
Most of the lightning people see takes place between a cloud and the ground. But lightning also occurs within a cloud, between a cloud and the air, and between two clouds. When Lightning occurs in the atmosphere, its electrical energy scatters in the air. This energy may damage airplanes but it does not cause harm on the ground. But lightning that strikes the earth may kill people or cause fire.