Background
Water is the world's most
precious resource. Besides being essential for life, it stabilizes our
climate, irrigates our crops, and lights our cities. Although 80% of
the Earth's surface is covered by water, only 0.5% is usablefresh water.
Humans are just one aspect of the larger ecosystem that is Planet Earth,
and we share this resource with plant and animal species who also need
water to survive.
Of the available fresh water
worldwide, 5% is used by households; 75% by agriculture; and 20% by
industry. In Colorado, 10% of fresh water is used in the cities, while
90% is used by the agricultural community.
Clean water is becoming harder
and harder to find, thus we must take steps to protect and improve this
resource. The impacts of pollution and population on water is the responsibility
of us all. This unit on water strives to increase knowledge and understanding
of water, watersheds, and environmental science, as well as providing
students with tangible opportunities to become stewards of their local
waterways.
Activity
This activity introduces
the concept of watershed. It will also help you to discover how much
water is on the planet and how much of it we can actually use.
Materials
- Blowup Earth Ball
- Measuring tools (1000
ml beaker and smaller containers)
- Video The Power of Water
- Copy of worksheet All
the Water in the World
Activity #1
Demonstration with blow-up
earth ball
Have everyone stand in a
circle. Toss the globe back and forth to each other spinning it when
it is thrown. Each time it is caught, notice where the right index finger
lands. Someone should record where each person finger falls when they
catch the earth ball: on ocean, land, lake. When everyone has caught
the ball once, figure out the percentage of time people's fingers landed
on water vs. land. Is it close to 80%?
Demonstration with milliliter
beakers
The earth is 80% water,
but not all of that water is fresh oraccessible. This demonstration
will help you visually understandwhat percentage of water is in the
oceans, icecaps and glaciers, groundwater, fresh water lakes, inland
seas and salt lakes, the atmosphere, and all rivers. After this activity
you will understand that the amount of fresh water available for use
is only a faction of the water on the planet. See accompanying student
worksheet.
Activity #2
Video
The National Geographic video
The Power of Water is an excellent introduction to water issues,
available from the Water Resource Educator. Length is 55 minutes. The
video is divided into 5 sections: Columbia River (10 minutes), The Great
Lakes (10 minutes), Everglades (10 minutes), Ogalalla Aquifer (10 minutes)
and the Colorado River and the Southwest (10minutes). See accompanying
video worksheet.
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