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1-2 How Scientists Work


Key Concepts
  How do scientists test hypotheses?
  How does a scientific theory develop?
Vocabulary
spontaneous generation
controlled experiment
manipulated variable
responding variable
theory

Reading Strategy: Outlining As you read, make an outline of the main steps in a controlled experiment.

 

Have you ever noticed what happens to food that is left in an open trash can for a few days in summer? Creatures that look like worms appear on the discarded food. These creatures are called maggots. For thousands of years people have been observing maggots on food that is not protected. The maggots seem to suddenly appear out of nowhere. Where do they come from?

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