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. Sometimes the rain, so necessary to the health of plants and animals, becomes contaminated or even poisonous, and harms or kills the life forms that need it.
Acid rain is a recent problem, caused by factories and other modern inventions, such as cars.
Smoke stacks from factories and cars release fumes and dangerous gases into the air. The fumes and dangerous gases combine with water and ice particles in the clouds and fall as rain. Acid rain is at least thirty times more acidic than normal rain. It can be very destructive, damaging forests, polluting water, and killing fish and animals. Try the Lightning and Other Wonders of the Sky Activity to learn more about the processes in the atmosphere.