Download Week 4 Ch1.3 Water

Earth’s Water
The Water Cycle
• Almost all of the hydrosphere is saltwater found in
oceans, seas, and some lakes.
• The amount of water on Earth never changes, but it
is constantly moving through the processes of
evaporation, condensation, and precipitation.
• Evaporation is when the sun’s energy causes water
to change into vapor or gas.
• Condensation is an excess of water vapor that
changes into liquid water after warm air cools.
• Precipitation is the release of moisture through
rain, snow, or sleet.
Earth’s Water
Bodies of Salt Water
• Seventy percent of the Earth’s surface is water,
primarily salt water.
• Salt water cannot be used for drinking, farming, or
manufacturing.
• Due to a growing population and the need for more
freshwater, some countries are focusing on the
desalination process, which removes the salt from
seawater.
• Desalination is expensive and is also controversial;
critics believe the process has negative environmental
and economic impacts.
Earth’s Water
Bodies of Freshwater
•
More than two-thirds of the world’s scarce freshwater
is frozen in glaciers.
•
Less than one-third of a percent of freshwater is found
in lakes, rivers, and streams and their tributaries.
•
Aquifers and groundwater are important sources of
freshwater found underground within the Earth.