Weather

Clouds are made of tiny water droplets or ice crystals suspended in the atmosphere. Meteorologists classify clouds by their height and shape — different types give clues about upcoming weather.

Precipitation is any form of water that falls from clouds to the Earth's surface. The type of precipitation — rain, snow, sleet, hail, or drizzle — depends on temperature in the cloud and at the surface. Different cloud types produce different precipitation.

The four seasons occur because Earth orbits the Sun tilted at 23.5° on its axis. This tilt means different hemispheres receive more direct sunlight at different times of year, causing temperature and daylight hours to change seasonally.

The water cycle (also called the hydrological cycle) describes the continuous movement of water between the oceans, atmosphere, land, and living things. It is driven by solar energy and gravity and provides the fresh water that all life depends on.

Wind is the horizontal movement of air from areas of high pressure to areas of low pressure. It is driven by differences in air temperature and pressure and is shaped by the rotation of the Earth (Coriolis effect).