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.
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.
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?
Science as Inquiry
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
History and Nature of Science
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