(Earth Science for ages 5+)
There are tiny forms of life that exist everywhere – in the ground, in water, on plants and animals, and even inside our bodies! These organisms are too small to see with the naked eye so you need a microscope to see them.
As such, they are called “microorganisms.” In fact, entire ecosystems rely on microorganisms to process and cycle certain nutrients and keep plants and animals healthy. One way to see how certain nutrients affect the microorganisms that are able to live in soil is to build Winogradsky columns with different nutritional conditions.
The video above can walk you through it, and the materials and instructions are listed below.
Four plastic bottles (with smooth sides and no ridges)
Two hard-boiled eggs
Four rubber bands
Warm place to store bottles
Adult supervision (Adult supervision at all times please)
- Prepare your bottles by first having an adult help you carefully cut off the tops of your four bottles and remove any wrappers on them. Then use the marker to label the bottles “Nothing,” “Egg,” “Paper,” and “Egg + Paper.”
- It is time to prepare your four columns. Start by filling the bottle labeled “Nothing” about 80% full of saturated mud water. Try to remove as much debris from the mud as possible, such as sticks and stones.
- In a separate bucket, mix some saturated mud water with one of your hard-boiled eggs. Once the egg is mixed in with the mud, add this mixture to the bottle labeled “Egg” until it is about 80% full.
- In a clean bowl (with no egg in it), mix together lots of mud water and shredded newspaper. Fill your “Paper” bottle about 80% full of this mixture and try to leave some extra for the next bottle.
- Finally, you want to add your second hard-boiled egg to the mud water and shredded newspaper mixture. Mix these together very well, and then fill your “Egg + Paper” bottle 80% full of this mixture.
- Using the plastic wrap, tightly cover each of the bottles and secure the plastic with a rubber band.
- Place your four columns in a warm place but avoid direct sunlight. It will take several days for the microorganisms to grow, but check on your columns every 4 days or so to see what changes are happening. Keep track of changes in color and whether you can see different layers separating in the columns. Let the ecosystems in your four columns continue to grow and observe the changes every few days for 5 weeks.
The process by which microorganisms cycle nutrients is called the biogeochemical cycle. In this cycle, nutrients are neither lost or destroyed, but continuously reused and recycled by the various organisms in a system.
Your four columns have four different mixtures of nutrients. As the microorganisms present in the saturated mud water cycle these nutrients, different gradients of nutrient concentrations emerge.
These gradients determine which microorganisms are able to live within different nutrient profiles, and you will likely see distinct layers form within the columns. It’s pretty neat to see how ecosystems process, share, and recycle resources so all forms of life within the ecosystem can survive!