CK12 Earth Science

(Marvins-Underground-K-12) #1

At the surface, the water will eventually undergo evaporation and reenter the atmosphere.
If the water is taken up by a plant and then evaporates from the plant, the process is called
evapotranspiration.


Figure 15.1: The Water Cycle. ( 20 )

All weather takes place in the atmosphere, virtually all of it in the lower atmosphere.
Weather describes what the atmosphere is like at a specific time and place, and may include
temperature, wind and precipitation. It is the changes we experience from day to day.
Climateis the long-term average of weather in a particular spot. Although the weather
for a particular winter day in Tucson, Arizona may include snow, the climate of Tucson is
generally warm and dry.


The physical and chemical changes that happen on Earth’s surface due to precipitation,
wind and reactions with the gases in our atmosphere are calledweathering. Weathering
alters rocks and minerals and shapes landforms at the Earth’s surface. Without weathering,
Earth’s surface would not change much at all. For example, the Moon has no atmosphere,
water or winds, so it does not have weathering. The footprints that astronauts made on
the Moon decades ago will remain there until someone (human or alien) smooths them out!
You would only need to spend a few minutes at the beach to know that Earth’s surface is

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