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Usable Water
is a limited resource and as the Earth's population continues to grow, water is becoming more important than ever before. All kinds of activities that are just part of "everyday life"
can affect water in significant ways.
Think about how you get around: do you drive or get a ride or do you walk, bicycle, or take the train or the bus?
How do you dispose of trash: do you recycle bottles, cans, and newspapers and put non-recyclables in waste baskets and garbage bins or do you just throw everything out and do things like putting wrappers in sewage drains or just dropping
used fast food containers out in the street? And how do you use water every day: do you leave the tap running while washing dishes, brushing your teeth, or just getting a drink?
All These Things
affect the quantity and quality of water that's available for people, plants, and animals to use.
Simple Activities
that you can do help highlight the fact that fresh water is not as plentiful as we might think.
A
World Water graphic is a good place to start. It shows how Earth, which is often called the Water Planet, actually has a very small amount of available fresh water.
The following activities help drive home the point!
 1. The Water Planet
Purpose: To understand that the earth's surface is mostly covered with water.
Materials:
Procedure:
- Make a data table with two columns. Label one "Water" and label the other "Land."
- Sit your group (family, friends, or classmates) in a circle and give one person the globe.
Have this person toss the globe to the person sitting to his or her right.
- When the globe is caught, note where the "catcher's" index fingers are pointing (either
water or land) and record this on your data sheet.
- Toss the globe around the entire group and record the results.
- Total the number of tally marks in each column and then divide the number in each column
by the total number of tally marks to get a percentage for each column.
Post Activity Discussion:
The results will show roughly 70% water and 30% land. What kind of water did most of the tally marks represent
(salt water or fresh)?
 2. But Not a Drop to Drink?
Purpose: To learn where the water on the planet is found and begin to understand
the limited quantity that is available to us.
Materials:
- one liter soda bottle
- an eyedropper
- a graduated cylinder
- blue food coloring
Procedure:
- Fill the one-liter soda bottle with tap water, and add enough blue food coloring to make it
a rich shade of blue.
- This bottle of water represents all the water on the planet. Pour three ml from it
into a graduated cylinder. The amount left in the soda bottle is water from the ocean.
- The amount in the cylinder is all the fresh water on the planet. This cannot
be used readily since most of this is frozen. Pour one-half of one ml into another
container. The amount left in the cylinder is the amount of water in frozen icecaps
and glaciers. The amount poured off represents liquid freshwater found in ponds, lakes,
rivers, and roundwater.
Post Activity Discussion:
What happens if the small amount of water that we do have available to us becomes
polluted? Can we get water from other sources? Desalination, or removing the salt
from ocean water, is very costly. What happens when we use too much water? Near
coastal areas, salt water encroachment can occur, and freshwater supplies can be ruined.
What can people do to avoid these problems?
Follow-up Activity:
Research an area of the country or world where fresh drinking water is scarce
and investigate the ways in which this country obtains its water.
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Watersheds
> Clean, Fresh Water