As the particles move they become oppositely charged and they separate. The positively charged particles go to the top of the cloud and the negatively charged particles sit along the bottom of the cloud. The negative particles along the cloud bottoms grow large and are attracted to the positive charges on the ground. When the attraction between the different charges becomes strong enough, electricity flows from the cloud to the ground. This flow of electricity is a lightning strike.
Lightning lasts only a fraction of a second, but it is filled with energy and is very hot.
It can reach temperatures that are much hotter than the sun. The heat of the lightning causes thunder. As the hot electrical charge passes through the air, it heats up the air. The heated air expands quickly and makes the loud noise we call thunder. Each year rain clouds pour trillions of gallons of water on Earth, giving life to plants and animals across the planet.