Challenge:
Make Your Own Water Cycle!
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To help you understand the earth's water cycle better, create
your own "mini-system" as a research project. Don't forget our
important themes, and you will be able to see them in action!
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1. All water moves about the planet.
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2. All water within the biosphere is recycled.
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Here are the materials that you need:
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-one large fish tank or other glass container (minimum 20 gallons)
-a glass or plastic divider, cut to fit the width of the fish
tank(divider should be one-half the height of the tank)
-silicone sealant (from auto parts or hardware store)
-soil
-grass seed or some type of small vegetation
-a glass cover, cut to fit on top of tank
-goldfish (optional)
**SOME PARENTAL SUPERVISION MAY BE REQUIRED
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Set up by following these instructions: (Look at the diagram that's
under the directions)
- The fish tank should be divided into two sections. One-third of
the tank is going to be the pond area, where you will soon put
in water and your goldfish. The remaining two-thirds is going
to be soil. To create these two sections, place the glass divider
in the tank one-third of the way from one end.
- Use a silicone sealant to make it watertight. Run a line of silicone
along each side of the divider where it meets the tank, and along
the bottom edge. Allow it to dry for at least twenty-four hours.
- When the divider is permanently set, the soil should be put in
the bigger section. Put the soil in so that it slopes upward from
the divider. This will eventually make a moisture slope for the
extra water run-off.
- Plant the grass seed or other plants, and allow time for it to
start growing and make root systems. This will probably take about
2 weeks. Water appropriately during this period, but be careful
not to over water or fertilize. Over watering will create mold
and mildew, while fertilization will burn the roots.
- Once the grass starts to grow, it is time to set up the fish-pond
section section of the tank.
- Fill the empty section of the tank up with water. Go to the top
of the glass divider but do not go over it. If you want to, you
can put your minnows or a goldfish in the water.
- Cover the tank with the glass plate and seal it by wetting the
rim of the tank. Your system is now enclosed, and the hydrologic
cycle is in operation. Within several days the processes taking
place should become visible. Water will evaporate from the pond
and transpire from the vegetation. This gaseous water will cool
on the glass plate and condense into droplets, which will precipitate
back down to the pond and soil sections of the system.
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Here is a diagram of what your mini-system should look like:
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Conclusion:
This mini-system represents the hydrologic cycle within the biosphere.
The water is locked in; there will never be any more or any less.
It is constantly being recycled, traveling to all the different
sections of the system. The system will work, and all will be
fine as long as the water quality is satisfactory. But when the
water becomes polluted, the cycle starts having problems.
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