How to Make a Biodome for a Science Fair Project

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A biodome is a contained sustainable environment with enough resources for organisms to survive. Scientists use these models to study ecosystems and the essential interactions between plants and animals and nonliving materials. Students can use biodomes to study how energy flows in an ecosystem, testing the plant maturation by fluctuating light conditions. They can observe how the different parts of plants, such as leaves, stems and roots, enable survival. They can also keep journals of the conditions in the biodome that allow for a self-contained environment to thrive on its own.

    Remove the labels from three 2-liter soda bottles.

    Cut the top off of Bottle #1 about 2 to 3 centimeters above the top curve. Cut the same bottle 2 to 3 centimeters below the bottom curve. Remove the bottom of the Bottle #1 to form a cylinder.

    Cut the top off of Bottle #2 only 2 centimeters below the top curve.

    Cut the bottom off Bottle #3 about 2 to 3 centimeters above the bottom curve.

    Punch a hole in one bottle cap with the tack. Make the hole bigger by pushing the perimeter of the hole back with the sharp end of the scissors. The hole needs to be big enough to thread the string through.

    Attach the cap to the cut-off top of Bottle #2.

    Dip the cotton string in water until it is soaked. Thread it through the hole in the cap. This string will act as a wick that pulls water into the soil.

    Turn the cut-off top of Bottle #2 with the cap upside-down. Fit it into the remaining bottom of Bottle #3.

    Slide the cylinder -- ie, Bottle #1 -- into the remaining bottom and over the inverted cut-off top.

    Add the top from Bottle #1 as the cover.

    Tape the sides of the cut bottles together to secure the biodome.

    Fill the bottom of the biodome with water until it reaches the cap.

    Pour soil into the inverted top with the cap. The string should thread into the soil. Make sure it is not pasted to the side of the bottle.

    Make a hole in the soil that is 2 centimeters deep. Place a seed in the hole, and cover it up with soil.

    Sprinkle the soil with water until the soil is moist.

    Put the second cap on the top of the biodome. Place the biodome in a sunny area so that the plant gets enough light to grow.

    Things You'll Need

    • 3 two-liter soda bottles
    • 2 bottle caps
    • Thick string
    • Scissors
    • Tack
    • Tape
    • Potting soil
    • Plant seed

About the Author

Kay Tang is a journalist who has been writing since 1990. She previously covered developments in theater for the "Dramatists Guild Quarterly." Tang graduated with a Bachelor of Arts in economics and political science from Yale University and completed a Master of Professional Studies in interactive telecommunications at New York University.

Photo Credits

  • Brand X Pictures/Brand X Pictures/Getty Images