2.1a Weather is the condition of the outside air at a particular moment.

2.1b Weather can be described and measured by:


•wind speed and direction

•form and amount of precipitation

•general sky conditions (cloudy, sunny, partly cloudy)

2.1c Water is recycled by natural processes on Earth.

•evaporation: changing of water (liquid)into water vapor (gas)

•condensation: changing of water vapor (gas)into water (liquid)

•precipitation: rain, sleet, snow, hail

•runoff: water flowing on Earth ’s surface

•ground water: water that moves downward into the ground

2.1d Erosion and deposition result from the interaction among air, water, and land.

•interaction between air and water breaks down earth materials

•pieces of earth material may be moved by air, water, wind, and gravity

•pieces of earth material will settle or deposit on land or in the water in different


•soil is composed of broken-down pieces of living and nonliving earth material

2.1e Extreme natural events (floods, fires, earthquakes, volcanic eruptions, hurricanes,

tornadoes, and other severe storms)may have positive or negative impacts on living