Why does lightning occur?

Lightning occurs due to the buildup and discharge of electrical energy in the atmosphere during a thunderstorm. Inside storm clouds, collisions between ice particles create positive and negative charges, with positive charges accumulating at the top and negative charges at the bottom. This separation of charges generates a strong electric field. When the field becomes intense enough, it causes a rapid discharge of electricity, producing a lightning bolt. Lightning can occur within a cloud, between clouds, or between a cloud and the ground. Thunder is the sound produced by the rapid expansion of air heated by the lightning strike.