7th Grade Science Student ebook

(Marvins-Underground-K-12) #1

UNIT 1 LIVING SYSTEMS


In the 1600s, people believed that
living things could come from
nonliving objects. For example,
unrefrigerated meat eventually
becomes full of maggots. People
living in the 1600s thought the
meat actually turned into maggots.
In 1668, Francisco Redi, an Italian
physician, did an experiment with
flies and jars containing meat. His
experiment showed that meat
does not turn into maggots. This
may have been the first controlled
experiment!


  1. Design an experiment to test
    the hypothesis that meat does
    not turn into maggots. Sketch
    your design and list the
    experimental and control
    variables.

  2. Present your experiment and
    results to your class. You could
    even give your presentation as
    if it were 1668.


1.2 Section Review



  1. Write a hypothesis for the following question: “When a plant is
    placed near a window, why does it lean and grow toward the
    window?”

  2. A good hypothesis can be tested with an experiment. Which of
    the following statements is the best hypothesis? Explain your
    answer.
    a. There were many students absent from class today.
    b. Many students were absent today because the flu is going
    around.

  3. Explain how you would test the hypothesis you chose in the
    question above.

  4. Use the illustration of an experiment below to answer
    questions a, b, and c.


a. What is the experimental variable?
b. What are the control variables?
c. Write a hypothesis that the experiment could be designed to
test.
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