Thursday, April 28, 2011

Creating a Microbial Biosphere

Grace and Jack loved, loved, loved making a microbial biosphere - which is a self-contained ecosystem in a jar. We talked about how microbes are living creatures that are so small that you can't see them without a microscope, but if enough of them grow together you can see their 'community.'

We also talked about how microbes can make us sick (and then we call them germs) but more often they help us! Microbes break down plants and turn them into compost and the microbes in our intestines break down food and can make certain vitamins. We also use microbes to make yummy food like yogurt, cheese, kefir, and some bread!

The ingredients needed to make a microbial biosphere are as follows: dirt, water, egg shells, cooked egg yolk, newspaper, and a large glass jar with a lid.

Here is how Grace and Jack made their microbial biosphere...

Step #1: Collect dirt from one source and be sure to use a container other than your jar. Remove any rocks, sticks, or leaves from the dirt.

Step #2: Add an equal amount of water to the amount of dirt you collected to make a muddy mixture. Stir together. If you collect dirt/soil from a water source like a pond or stream be sure to use water from the same source (in a separate container). If you collect dirt from your garden (as we did), you can use tap water.

Step #3: Shred newspaper and add it to your mud mixture. One page of shredded newspaper should be used per 1 liter jar.

Step #4: Add cooked egg yolks to your mud and newspaper mixture. You will need 1/2 teaspoon of egg yolk per 1 liter jar (usually there are 2 teaspoons of hard-cooked egg yolk in one egg).

Step #5: Add 1 1/2 teaspoons of crushed egg shells per 1 liter jar. One egg typically yields 1 teaspoon of crushed egg shells.

Step #6: Transfer the mud mixture to your glass jar, filling it about 2/3 full. Cover your jar tightly.

Step # 7: Place your jar in a well-lit place but be sure to store your microbial biosphere out of direct sunlight or lamplight. Your biosphere should be kept at room temperature.

This science experiment was fun for us to put together and it will be fascinating to watch our microbial biosphere change over the next several weeks and months. It typically takes at least 3 to 4 weeks to start seeing microbe colonies. There will be so much for us to talk about and to learn about what is happening inside of our jar (and why)!!!

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