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Active Time
45 minutes to 1 hour
Total Project Time
3 or more days
Key Concepts
Microorganisms, ecosystem, Winogradsky column
Three plastic bottles with the tops cut off are filled with mud and covered with plastic wrap


Our planet recycles and reuses everything on it that is needed to support life. It is an amazing, giant recycling system called the biogeochemical cycle. You can actually model this on a small scale by using a plastic bottle and mud to build what is called a Winogradsky column. In this activity, you will build your own Winogradsky columns and investigate how including different nutrients can affect which soil microorganisms flourish and which fail.


Teisha Rowland, PhD, Science Buddies
Sabine De Brabandere, PhD, Science Buddies
This activity is not appropriate for use as a science fair project. Good science fair projects have a stronger focus on controlling variables, taking accurate measurements, and analyzing data. To find a science fair project that is just right for you, browse our library of over 1,200 Science Fair Project Ideas or use the Topic Selection Wizard to get a personalized project recommendation.


  • Four clean plastic water bottles, 500 milliliters each. Bottles that have smooth sides (no ridges), and are taller and narrower in shape work best.
  • Scissors
  • Knife (optional)
  • Permanent marker
  • Ruler
  • Rubber boots and old clothes that can get muddy (optional)
  • Access to a muddy stream, pond, lake, or marsh
  • Gloves
  • Shovel or trowel
  • Two buckets
  • Newspaper (1/4 sheet) or an equal amount of plain paper shredded into tiny rectangles.
  • An egg yolk
  • Two large mixing bowls
  • Measuring cup
  • Wide stick, for packing mud into the bottles
  • Measuring teaspoon
  • Adjustable desk lamp with 13-watt compact fluorescent bulb (optional)
  • An empty surface, such as on a desk or table, that is at a warm room temperature (about 72 to 78 degrees Fahrenheit). It should not receive any direct sunlight, but if you are not using a desk lamp, the area should be near a very sunny window.
  • Plastic wrap
  • Plastic trash bags or grocery bags
  • Four rubber bands
  • Cardboard box or brown paper bag
  • Flashlight



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Active Time
45 minutes to 1 hour
Total Project Time
3 or more days
Key Concepts
Microorganisms, ecosystem, Winogradsky column
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