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Spontaneous Generation?
Discovery of a New World of Life Forms

From the time of the ancient Romans, through the Middle Ages, and until the late nineteenth century, it was generally accepted that some life forms arose spontaneously from non-living matter. People thought new life just appeared - coming out of other substances.

For example, a seventeenth century recipe for the spontaneous production of mice required placing sweaty underwear and husks of wheat in an open-mouthed jar, then waiting for about 21 days, during which time it was alleged that the sweat from the underwear would penetrate the husks of wheat, changing them into mice.

As scientific experimentation became more systematic in the 1700s, scientists questioned some of the old theories and experimented to find new answers. In 1768, the Italian naturalist Lazzar suggested that perhaps the microorganisms in the air could cause spontaneous generation. He tested his theory by placing meat in open and closed jars.

Microscopes revealed the organisms that appeared to arise spontaneously. It was quickly learned that to create "animalcules," as the organisms were called, you needed only to place hay in water and wait a few days before examining your new creations under the microscope. Soon it was discovered that boiling would kill microorganisms, and experiments were conducted to disprove that organisms could spontaneously appear.

Try This: Organisms Everywhere
The hay infusion is a time-honored method for securing bacteria for study. Test the hay infusion method yourself! Here's how:

Pour hot water on a handful of hay, and filter the fluid through blotting paper. Place the fluid in a glass dish, and cover with a piece of glass to keep out the dust. When the fluid begins to appear turbid, bacteria will be abundant. Take a drop of the fluid to make a slide and examine under the microscope.

How clean is the air we breathe? You can find out by doing a simple test. You will need a dark room and a flashlight and your bed pillow. Take your pillow into a dark room and hit it a couple times. Aim the beam of your flashlight just over the pillow. What do you see?

National Science Education Standards

Science as Inquiry
Current scientific knowledge and understanding guide scientific investigations. (5-8)

Scientists develop explanations using observations (evidence) and what they already know about the world. Good explanations are based on evidence from investigations. (K-4)

Scientists review and ask questions about the results of other scientists' work. (K-4)

Science advances through legitimate skepticism. Asking questions and querying other scientists' explanations is part of scientific inquiry. (5-8)

Science and Technology
People have always had questions about their world. Science is one way of answering questions and explaining the natural world. (K-4)

History and Nature of Science
Science and technology have been practiced by people for a long time. (K-4)

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