Embedded Files
Interactive Vocabulary
Groundwater: water that collects underground in cracks and spaces in rock
Surface Water: any body of water above ground, including streams, rivers, lakes, wetlands, reservoirs, and creeks
Watershed: a land area that channels rainfall and snowmelt to creeks, streams, and rivers and eventually to outflow points, such as reservoirs, bays, and the ocean
Related Vocabulary
Related Vocabulary
Aquifer: An underground storage area for groundwater.
Artificial reef: a man-made structure that provides a habitat for aquatic organisms like fish
Dependence: the state of relying on or being controlled by someone or something else.
Irrigation: the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns
Ocean systems: the complex, interconnected ecosystems that make up the world's oceans
Oil Spills: release of a liquid petroleum hydrocarbon into the environment, especially the marine ecosystem, due to human activity
Overfishing: deplete the stock of (a fish).
Recharge zones: an area where surface water seeps into the ground and replenishes an aquifer
Runoff: The draining away of water
Springs: an area where surface water seeps into the ground and replenishes an aquifer
Water table: The level that water reaches. This can rise and fall depending on the level of precipitation.
Wells: a hole drilled into the ground to access water contained in an aquifer.
Text
Text
Water on Earth
Earth is sometimes called the blue planet because of the abundance of liquid water on
its surface. The hydrosphere is the system containing all the solid and liquid water on
Earth. About 70 percent of Earth’s surface is covered with water. Most of the water that
covers Earth’s surface is salty seawater. Seawater is water from a sea or ocean that has
an average salinity of 35 ppt. The salinity of seawater changes in areas where rivers
enter the ocean. There, seawater becomes brackish. Brackish water is freshwater mixed
with seawater.
Life, as we know it, cannot continue without freshwater. Freshwater is water that has
less than 0.2 percent salt content dissolved in it. Freshwater on Earth is scarce. More
than two-thirds of Earth’s freshwater is frozen. The rest is either gas or liquid water, and
most is stored underground. Less than 1 percent of Earth’s liquid freshwater is on the
surface in streams and lakes. The water that fills lakes and rivers is surface water. On
the other hand, water that is stored in cracks and pores beneath Earth’s surface is
Groundwater.
Human Influences on Earth’s Water
As the human population increases, so does its impact on water usage. Humans also use
water in ways that other organisms do not. People wash cars, do laundry, and use water
for agriculture, recreation, and transportation. Unfortunately, human activity can interfere
with the health of groundwater and surface water in a watershed in harmful ways. We
can try our best to have a beneficial influence on Earth's water to offset our harmful influences.
Mini Lessons
Keeping our water clean
Keeping our water clean
7.11: Earth and space. The student understands how human activity can impact the hydrosphere. The student is expected to:
7.11.A: analyze the beneficial and harmful influences of human activity on groundwater and surface water in a watershed; and
7.11.B: describe human dependence and influence on ocean systems and explain how human activities impact these systems.
Page updated
Report abuse