Formulating Hypotheses

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Formulating Hypotheses
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What it is.

• Science advances by formulating and testing
  hypotheses. An hypothesis is really a temporary
  explanation, a kind of educated guess about what
  will happen under certain conditions.
• A hypothesis usually begins as an answer to a
  question.

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Continued

• Question Do plants need light to grow?
• Ex. If green plants need light to grow, then
  only plants kept in light will display growth.
• Most times it is an If then statement.
• But ALWAYS is a statement that has a definitive
  answer, or one that can be answered yes or no.

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Take the following and make an hypothesis.

• Do living things give off CO2 when they digest
  food?
• A scientist thinks that living things give off
  carbon dioxide gas as they break down food. He
  or she predicts that carbon dioxide can be
  detected as an organism digests food.

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Whats the question? Formulate an hypothesis.

• Some students were investigating what made their
  classmates get colds. One student believed that
  those who took vitamin C every day got fewer
  colds than the rest of the students.

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Whats the question? Formulate an hypothesis.

• Another student was interested in raising
  tropical fish. She believed that fish that were
  given Phillip Chons Formula 1 food would
  produce more offspring than those fed Kaitlyn
  Gortners Golden Flakes.

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Facts about hypotheses

• You can prove them to be untrue, but you cannot
  prove them to be true.
• This means you can only support your hypothesis.
• The more a hypothesis is supported, the greater
  its power to explain the phenomenon.

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Bacteria

• Bacteria are microscopic creatures found almost
  everywhere. They are useful to biologists in
  many different kinds of experiments. For each of
  the following problems involving bacteria, form
  an hypothesis to make a prediction.

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Temp. and reproduction

• Does the temperature at which bacteria are grown
  affect their rate of reproduction?

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Food and reproduction

• Does using up the nutrients they are feeding on
  affect the rate of reproduction of bacteria?

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Vitamins and reproduction

• Some bacteria require certain vitamins in the
  material in which they are grown. Does bacterium
  X require vitamin B12 for reproduction?

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Aspirin and reproduction

• Does aspirin inhibit the reproduction of bacteria?

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• The questions and hypotheses you develop must be
  typed.
• I do not accept hand-written hypotheses.

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• END.
• STD LAB set up follows.

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STD Lab

• Tomorrow we will be mating with each other. You
  will have five partners that you will share
  bodily fluids with (one at a time). One
  individual in class will be contaminated with an
  STD at the start of the experiment.
• What question(s) could be asked about the spread
  of the disease in class? Choose one question to
  answer. Next, write a testable hypothesis that
  predicts the results (a best guess answer to the
  question).
• Your hypothesis must be signed off by me before
  you can begin the lab.