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44 Cards in this Set
- Front
- Back
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How do scientists test a hyptheses?
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By an experiment, a controlled experiement when possible.
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How does a scientific theory develop?
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When the evidence from many experiments is well supported.
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The idea or explanation that life could come from nonliving things.
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Spontaneous generation. (just a hyptheses).
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Give some examples of the HYPOTHESES "SPONTANEOUS GENERATION".
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Maggots from meat, mice from grain, beetles from poop.
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Who proposed that maggots don't just come from meat or from non-living things and what did this scientist do?
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Francesco Redi, he said that maggots appear on meat because flies lay eggs on it.
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What was Redi's hypthesis?
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Flies produce maggots.
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How did Redi test his hypothesis that flies produce maggots?
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By a controlled experiment. all variables were controleed except the gauze covering the jars to keep the flies off.
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In a controlled experiment how many variables are tested at a time?
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one at a time,
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What was the manipulated variable in Redi's experiment?
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The presence or absence of gauze.
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What did Redi's experiment do?
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Helped dis-prove the hypothesis of spontaneous generation.
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What is a controlled experiment?
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An experiment where only one variable is changed at a time while all other variables are controlled, or unchanged.
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In a controlled experiment, what variable is deliberately changed?
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The manipulated variable, like the gauze covering in Redi's experiment.
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What is the responding variable in an experiment?
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The variable that is observed, and changes in response to the manipulated variable.
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What was the responding variable in Redi's experiment?
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Whether or not maggots would appear.
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Scientific experiments have ________________ of _______________.
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standards of documentation.
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What do scientists do so that other scientists can repeat and test the same experiment?
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Record & analyze their results.
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Scientists use the _____ from an _____________ to evaluate the _____________ and draw a _________________.
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data
experiment hypthesis conclusion |
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By drawing a conclusion, scientists do what?
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They use the evidence from an experiment to determine whether the hypothesis was supported or refuted.
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In Redi's experiment, did his results support or refute his hypthesis.
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Supported his hypthesis that maggots come from flies.
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What is a Null Hypthesis
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In invalid hypothesis
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What was one of the first scientific experiments of proper scientific inquire?
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Redi's
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Does a single occurrence of an experiment establish it as a fact?
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No,scientists repeat and test other scientists experiments
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What scientist tested Redi's findings and what was his findings?
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Needham tried to prove sponteous generation could occur under the right conditions, gravy boiled but he left the flask open then lots of microorganisms were in the gravy after a few days.
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Was Needham's test with the gravy accurate?
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No
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Who tested and improved upon Redi's and Neeham's findings?
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Spallanzani
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What did Spallanzani's investigation show?
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That microorganisms will not grow in boiled and sealed gravy but only in boiled gravy that is open to the air.
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What variable was controlled in Spallanzani's experiment?
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Gravy was boiled, flasks used.
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What variable was manipulated in Spallanzani's experiment?
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One flask left open and the other one was sealed.
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Who created a microsope in 1673 that identified micro-organisms, and what did he call these microorganisms?
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Anton van Leeuwenhoek, he called them animalcules.
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Did the existance of newly found microorganisms make it easier for scientists to come to an agreement of the truth about spontaneous generation>
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No, for the next 200 years scientists could not agree if the microorganisms were alive or how they even came in existance.
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Who tried to re-prove spontanous generation and was he correct?
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Needham reproved it but then Spallanzani's tests proved he was wrong. No living things come from non living things.
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What is a key assumption is science?
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That experimental results can be reproduced because NATURE behaves in a consistent manner.
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When one particulare variable is manipulated in a given set of variable, will the results always be different or the same?
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The same.
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What did Spallanzani conclude by his experiment?
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That nonliving gravy did not produce living things. The living microorganisms came from other ones that entered the open jar.
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Who used a long curved flask to improve upon the boiled gravy type of test?
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Louis Pasteur, he proved that all living things come from other living things, not just from air.
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Which scientists finally settled the argument that living things don't come from non-living things?
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Louis Pasteur
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It is always possible to test a hypOhesis by an experiment, TRUE OF FALSE.
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FALSE
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How do animal field studies differ from controlled experiments?
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Animals are observed by watching them, etc.
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What is a theory?
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A well-tested explanation that unifies a broad range of observations.
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What theory is considered absolute truth?
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No theory is, but a usefule theory rules over other ones.
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How did the design of Pasteur's flask help him successfuly refute the hypthesis of spontaneous generation?
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The curved flask didn't allow microorgamisms to enter until he broke the flasks neck, then it started growing microorganisms.
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Name an example of a field study of cancer-causing chemicals?
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Scientist would not include volunteers with other serious health problems, but only
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Name some field studies:
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studying animals how they interact with eath other, studying humans that have been exposed to cancer causing chemicals and compare to people not exposed.
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A _________ enables scientists to make accurate _____________ about new situation.
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theory
predictions |
