How Lightning Works Lightning transfers electrons from the atmosphere to Earth. Electrons build up in clouds because wind causes them to rub together (Charging by friction). The negative charges in the clouds push the negative charges in the ground away leaving positive charges on the surface (Charging by induction). Once enough negative charge builds up in a cloud, it repels so strongly (second Law of Electric Charges) that it jumps through the air (an insulator) and strikes the positively free powerpoints at www.worldofteaching.com