Kids, our planet is made up of millions of different species which try to live together. Man is a species, just as animals like dogs, cats and fish are. Some species are so small that you can't even see them. Today you'll learn about fungus and microbes ("small life")
Please note: All chemicals and experiments can entail an element of risk, and no experiments should be performed without proper adult supervision.
First, put a piece of bread and a teaspoon of water into a ziploc plastic bag, seal it, and let is sit at room temperature for 3 or 4 days. You'll notice that the bread is now covered in green mold. Mold is a furry growth of fungus found on the surfaces of decaying food or in moist, warm places. A fungus is a tiny non-flowering plant with no chlorophyll, roots, stems, or leaves. The fungus could have gotten onto the bread by a variety of means, such as transfer from your hands.
Secondly, we'll do a test for microbes that cause feet to smell bad. Feel smell bad when very tiny plants or animals grow on our skin. Have an adult boil 1/2 cup of water. Sprinkle in 4 envelopes of unflavored gelatin and dissolve it. Pour this into a clean mayonnaise jar and set it on its side (let the extra pour out and dispose of it). Put on sneakers without socks and go play outside. After about 3 hours the gelatin should be hard and your feet should be smelly. Take a swab and rub it between all your toes. Carefully brush the gelatin with the cottin tip in long strokes. Close the jar and put it in a warm dark place for 4 days.
Inside your shoes it's dark, warm, and damp. This is perfect for microbes, which will grow and grow. The mayo jar is similar, and the microbes survive by eating the gelatin. You'll see grooves in the gelatin after 4 days showing where the microbes are living and eating. If you open it, you'll smell something much worse than smelly feet. It smells really horrible. Either dispose of the jar intact or, if you want to save it, fill it with hot water and then wash with soap and water. DON'T touch inside the jar at first, and keep washing your hands.
You can collect microbes from many places, such as from the drinking fountain, the cafeteria, or even from fellow classmates at school!
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Kathleen Carrado Gregar, PhD, Argonne National Labs
[email protected]
August-September 1996
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Reference: The Internet at: Bill Nye, The Science Guy (http://nyelabs.kcts.org/demo/) and Beakman & Jax (http://www.nbn.com/youcan/feet/).
